Seawater chloride ion concentration measuring device based on dual-fiber optical grating

Abstract

The invention discloses a seawater chloride ion concentration measuring device based on a dual-fiber optical grating. The seawater chloride ion concentration measuring device comprises a shell, wherein a solution tank is arranged inside the shell, a display board which is connected with a circuit control module is arranged on the outer surface of the shell, the input end of the circuit control module is connected with a photoelectric detection module, the output end of the circuit control module is connected with a laser module, the output end of the laser module is connected with the input end of the photoelectric detection module through a first fiber optical grating sensor and a second fiber optical grating sensor respectively, and a heat shrink pipe is arranged on the outer surface of the second fiber optical grating sensor. The seawater chloride ion concentration measuring device is high in accuracy for measuring seawater chloride ion concentration, strong in stability, low in cost, small in volume, convenient to carry, and suitable for wide popularization and application.

Description

technical field [0001] The invention relates to a device for measuring the concentration of chloride ions in seawater in the technical field of optical fiber sensing, in particular to a device for measuring the concentration of chloride ions in seawater based on double optical fiber gratings. Background technique [0002] The measurement of chloride ion concentration in seawater is widely used in many fields such as marine environmental monitoring, petroleum, import and export trade, and military navigation. It is especially important for environmental protection and monitoring of water quality resources worldwide in recent years. Research value and scientific significance. Seawater salinity is an important parameter for studying marine fish farming, ocean circulation, ocean dynamics, rainfall, seasonal climate prediction and marine resources. The traditional measurement method of chloride ion concentration in seawater is mainly based on electrochemical method, which has th...

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Problems solved by technology

The traditional seawater chloride ion concentration measurement method is mainly based on electrochemical methods, the disadvantages are low sensitivity, cumbersome operation and inaccurate measurement

[0003] In recent years, many universities and research institutes have carried out some research and application of fiber gratings in the measurement of chloride ion concentration in seawater, but because fiber gratings are extremely sensitive to various factors such as strain and temperature, and traditional fiber grating sensing systems are The instrument is very expensive, which makes its engineering application difficult

[0004] Chinese patent 200920293017.5 discloses a device for dynamic and real-time detection of liquid concentration. The solution concentration sensor of the device is a bare long-period fiber grating, and two fiber gratings are cascaded to improve measurement accuracy, but no consideration is given to long-period fiber grating transmission. Sensitive characteristics are extremely sensitive to temperature and strain. When measuring solution concentration, small changes in solution temperature or sensor stress will also cause large measurement errors, and the measured results are unstable and easily affected by ambient temperature.

[0005] Chinese patent 201220302291.6 discloses a system for measuring the concentration of chemical solutions using fiber gratings. The measurement system includes a broadband light source, a spectrum analyzer, and a fiber grating sensor. The broadband light source and spectrum analyzer are very expensive, and the system has a complex structure and volume. Huge, cumbersome to build, inconvenient to carry, poor mobility, not conducive to the measurement that needs to go to the industrial site

[0006] To sum up, the existing methods of using fiber gratings to measure the concentration of chloride ions in seawater have large errors, are easily affected by the environment, expensive instruments, large systems and complex construction, and cannot meet the current rapid development of industrial and agricultural development needs.

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