Double-fiber grating diaphragm type pressure sensor and low-pressure calibration system and method thereof

Abstract

The invention provides a double-fiber grating diaphragm type pressure sensor and a low-pressure calibration system and method thereof. The double-fiber grating diaphragm type pressure sensor comprises a base with an open cavity, a double-fiber grating low-pressure diaphragm is installed on the open face of the cavity, a medium leading-in connector with a pressure leading-out hole is arranged on one side, located on the bottom face of the cavity, of the base, a high-pressure diaphragm is arranged at the cavity end of the pressure leading-out hole, and a commutation hole leading to the cavity is formed in the side face of the pressure leading-out hole. A pressure change valve is arranged; the low-pressure calibration system comprises a pressure signal demodulation module, a liquid level measuring device and a water tank and can calibrate one or two or more than two double-fiber grating diaphragm type pressure sensors, and the pressure sensors take the wavelength difference of the two fiber gratings as sensing signals for measuring pressure. The influence of the temperature on the measurement result is eliminated, and the measurement resolution is improved; and the calibration method is high in calibration precision, and the difficulty of pressure sensor calibration under the ultra-low pressure condition is effectively solved.

Description

technical field [0001] The invention belongs to the field of optical fiber pressure / liquid level measurement, and in particular relates to a high-sensitivity double-fiber grating diaphragm pressure sensor and a liquid level calibration testing device and method thereof. Background technique [0002] With the rapid development of my country's economy and technology, people have put forward higher and higher requirements for the safe operation of pipelines transporting water, oil, natural gas and other fluids, as well as complex pipelines on industrial equipment and large-scale mechanical equipment. High-precision monitoring of pressure or liquid level inside gas / liquid pipelines or containers. Most traditional pressure sensors are mechanical and electromagnetic pressure sensors. Mechanical pressure sensors are mostly used for single-point pressure measurement and display, and the measurement data cannot be transmitted to a computer for analysis and processing; electrical pres...

AI Technical Summary

Problems solved by technology

Mechanical pressure sensors are mostly used for single-point pressure measurement and display, and the measurement data cannot be transmitted to a computer for analysis and processing; electrical pressure sensors are usually poor in anti-electromagnetic interference, and cannot be safe and reliable for a long time in harsh environments such as high temperature and strong electromagnetic interference. Work, long-distance transmission of measurement signals is difficult, because the sensors cannot be connected in series, in a large-scale multi-point pressure monitoring system, a large number of data transmission signal lines are required

[0003] Based on the above-mentioned high-precision, distributed pressure or liquid level measurement requirements, among the types of pressure sensors that have been developed so far, pressure sensors such as piezoresistive / piezoelectric and microwave resonance still have electrical signal transmission and extraction accuracy at low pressure. However, the fiber optic sensor has been extensively studied due to its advantages of no electromagnetic interference, high measurement accuracy, corrosion resistance, etc., especially the fiber optic FBG pressure sensor, because of its simple and reliable physical structure, small size and automatic temperature compensation, etc. Advantages, especially suitable for working in harsh environments such as high temperature and radiation

However, there is still relatively little research on the testing device and coefficient calibration method for low-pressure, distributed FBG pressure sensors.

And there are some obvious defects, such as the interface between the sensor and the test device, there are problems such as not easy to disassemble, easy to damage the sensor, and complex structure; in addition, there is no relevant specification for the calibration of the pressure coefficient, and it is easy to ignore the temperature and pressure crossover of the optical fiber FBG sensitive issue

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