A fbg pressure sensor based on diaphragm and flexible hinge lever mechanism

Abstract

The invention discloses a FBG pressure sensor based on a diaphragm and a flexible hinge lever mechanism, which comprises: a casing assembly, which has two optical fiber outlets at the top and a pressure measurement channel at the bottom; the diaphragm is arranged in the pressure measurement channel; The force rod is located above the diaphragm and is connected to the middle of the diaphragm; the lever mechanism is located in the inner cavity of the housing assembly, including a support frame and a flexible hinge lever arranged on the support frame, and the flexible hinge lever is located on the force transmission rod. Above; the pressure measuring fiber grating and the temperature measuring fiber grating are arranged on the flexible hinge lever and arranged at intervals, and the pigtails of the pressure measuring fiber grating and the temperature measuring fiber grating are respectively passed through an optical fiber outlet. Through the above structure, pressure sensitization can be achieved, and temperature self-compensation can be performed, thereby improving measurement accuracy and sensitivity.

Description

technical field [0001] The invention relates to the technical field of fiber grating sensing and monitoring, in particular to a fiber grating pressure sensor. Background technique [0002] In recent years, fiber grating sensors have been widely used due to their advantages such as explosion-proof, light weight, small size, corrosion resistance, anti-electromagnetic interference, high reliability, and easy networking. However, since the pressure sensitivity of the bare fiber grating is very low, only about 3pm / Mpa, the too low sensitivity cannot meet the high-sensitivity measurement in practical applications. Therefore, some sensors adopt pressure sensitization technology. Traditional pressure sensitization includes FBG pressure sensitization based on polymer-filled metal tubes and FBG pressure sensitization based on elastic materials (FBG, Fiber Bragg Grating, Fiber Bragg Grating). [0003] In the traditional FBG pressure-sensitizing method based on polymer-filled metal tub...

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Problems solved by technology

However, as the polymer material will change with the temperature, the Young's modulus will change greatly, which will affect the measurement accuracy; and it will be easily damaged in corrosive environments such as oil and seawater, which makes it not suitable for large temperature changes. Pressure measurement in large and harsh corrosive environments

In the traditional FBG pressure sensitization method based on elastic materials, the fiber grating is directly pasted on the center of the thin sheet, and the grating is strained by the deformation of the diaphragm to achieve the sensitization effect. Chirp, no temperature compensation either

[0004] In addition, in the article "High Sensitivity Fiber Bragg Grating Pressure Sensor Based on Elastic Sheet Packaging" published in "Optoelectronics·Laser" Volume 22 Issue 5 in May 2011, the deformation caused by the pressure response is directly transmitted through a flat circular sheet. Converted to the axial strain of FBG, due to the stretching of FBG and its own elastic-optic effect, it is converted into the change of the reflected wavelength of the FBG center, thereby achieving high-sensitivity signal detection, but the pressure-bearing capacity of the film is limited, which will lead to Its pressure measurement range is not high; and there is no temperature self-compensation, temperature changes will affect the measurement accuracy

In the article "A High-Sensitivity Fiber Bragg Grating Pressure Sensor" published in "Optoelectronics·Laser" Volume 23, Issue 11 in November 2012, by pasting FBG on the L-shaped beam, when the pressure acts on one end, it is a frustum structure When the piston is on the piston, the piston will push the L-beam to bend through the cone, so that the FBG will be strained. Although the sensor achieves pressure sensitivity, its sensitivity effect is still insufficient.

In the article "High Sensitivity Fiber Bragg Grating Pressure Sensor Based on Sinusoidal Mechanism Force Amplification Principle" published in "Journal of Instrument and Apparatus" Volume 27 Issue 7 in July 2006, its flat circular thin plate structure can make the sensitivity reach a higher value , but the bending structure of the optical fiber is easy to bend the optical fiber, which seriously affects the service life of the optical fiber

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