Optical fibre grating sensor based on Bourdon tube as energy changer and method thereof

Abstract

The invention relates to optical fiber grating sensor and method based on bourdon tube used as transducer. It includes one bourdon tube pressure transducer, one optical fiber grating cantilever, optical fiber coupler, transmitting optical fiber, package shell, fastening location device, sealing device. The bourdon tube makes its cross section incline to circular under the action of inner pressure, compel free end 13 to make a move which is sent to cantilever 14 to make it flexural strain by connecting point 13. The optical fiber grating 4, 5 pasted under the cantilever 14 are respectively suffered the tension strain or compressive strain epsilon to make optical fiber grating Bragg wave length drift. The tested pressure and temperature can be known by testing the wave length change of the two optical grating.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to a fiber grating sensor and a method based on a Bourdon tube (also called a spring tube) as a pressure transducer. Background technique [0002] The measurement of pressure and temperature has long been a very important parameter in the modern industrial production process. In petrochemical industry, exploration and production of oil and gas fields, aviation instruments, underwater operations and other fields, electrical quantity sensors are generally used to measure pressure and temperature separately, and then the signals are transmitted to the terminal through cables for signal processing. Due to the poor adaptability of electronic components to harsh environments (every 10°C increase in temperature will double the failure rate of electronic instruments), weak electrical signals are prone to electromagnetic interference (inherently deficient in electromagnetic measurement), spe...

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Problems solved by technology

[0005] The existing Bourdon tube test pressure technology is to paste the resistance strain gauge on the place with the largest strain on the Bourdon tube. The resistance strain gauge used in it is easy to cause signal drift under the temperature change or electromagnetic field interference, and the increase of temperature will make the strain The failure rate of the amplifying system of chips and electric signals is greatly increased, such as (PRC Utility Model Patent Application Specification CN85 2 03516 U)

The existing fiber grating pressure and temperature sensors are rare, and the processing technology and modular design are immature, the structure is complex, and the sealing is difficult. For example, Tsinghua University once proposed to use a circular pressure transducer combined with a cantilever beam. Institution (Invention Patent Application Specification of the People's Republic of China, Application No. 02121327.5, Publication No. CN1384341A)

However, the existing Bourdon tube fiber grating pressure sensor does not use a double grating structure, which cannot realize the real-time separation and detection of pressure and temperature, and the material used in the cantilever beam is polymer such as plexiglass. No matter in the temperature measurement range, stability, There are big problems in terms of repeatability and reliability, and it cannot be practical

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