Multi-point optical fiber mash gas sensing system based on optical fiber caching machine

Abstract

The invention relates to a multipoint gas sensing system based on an optical fiber buffer, which comprises an address encoder, a double-wavelength light source, a multipoint optical fiber sensing network and a demodulator. The address encoder generates an address code and a read-write control signal of different monitoring points; each detecting unit of the multipoint optical fiber sensing network adopts a buffer structure introduced with a gas absorbing chamber in an optical fiber loop; a double-loop coupling all-optical buffer and a polarization type all-optical buffer can be adopted; under the control of a write signal, the optical signal of the address code is written into the optical fiber loop of the detecting unit and circularly absorbed by the gas many times; the absorbed optical signal is read out and sent to the demodulator for photoelectric conversion, comparison with the reference light, address decoding and data processing in order to gain the gas concentration in different points and realize the multipoint gas monitoring. The system gains the good effects through improving the structure of the absorbing chamber, adding an optical amplifier, a polarization control and a device with the wavelength of 1665nm, and is used in the monitoring of the gas which has the wavelength of 1665 nm and is near provided with an absorption peak.

Description

technical field [0001] The invention relates to a multi-point gas sensing system based on an optical fiber buffer, and belongs to the technical field of measuring gas concentration by optical fiber sensing systems. Background technique [0002] Energy shortage has become an important factor restricting the sustainable development of my country's current national economy. Among the primary energy sources (coal, nuclear energy, oil, natural gas, wind power, tide, solar energy), coal is the most important primary energy source in my country and plays a pivotal role. However, the current safety situation in coal mines is very worrying. Among various mine disasters, gas explosion ranks first, so gas monitoring technology has always been an important technology for coal mine safety. After long-term research and development, a variety of series of gas detection instruments have been developed: such as using the height change of the flame to detect the gas test lamp; the gas teste...

AI Technical Summary

Problems solved by technology

This means that it is very difficult to send light out of the fiber through a 50cm absorption chamber and then converge into the fiber

Although feasible in principle, it is not technically feasible

Moreover, the absorption length of 50cm is too large for a sensor head, and it is greatly affected by the environment.

In a mine full of dust and moisture, practical application is impossible

Moreover, when the gas concentration in the environment changes, the concentration in the gas chamber of the sensor should also change accordingly, but an excessively large gas chamber will inevitably lead to a large difference between the gas concentration in the gas chamber and the gas concentration in the environment, or lag in time, reducing the Sensor sensitivity and response speed

Therefore, although optical fiber gas sensors have been proposed for many years, and many research institutions have reported their research results in the laboratory, they have not been practical so far, and it is difficult to use them in the narrow space of the harsh coal mining face.

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