Portable optical-fiber-sensing apparatus for detecting concentration of flammable and explosive gases and hazardous gases

Abstract

A portable optical-fiber-sensing apparatus for detecting concentration of flammable and explosive gases and hazardous gases relates to applications of optical fiber sensing to the field of security monitoring on flammable and explosive gases and hazardous gases of coal mines, non-coal mines and petrochemical depots. An optical sensor is used for detection of methane, hydrogen sulfide, carbon monoxide, carbon dioxide or alkanes oil gas, instead of a catalytic combustion sensor or an infrared sensor. The apparatus is high in precision, rapid in response, not affected by temperature and humidity, non-electric intrinsically safe, and long in service life. The optical fiber gas concentration sensing system consists of an optical fiber sensor, an optical-path circuit module and a system software. Different gases are modulated with different-wavelength lasers, and the lasers are transmitted to an open-type gas chamber via an optical fiber. Multiple pairs of lens reflectors are disposed in the gas chamber and make the lasers reciprocate in the gas chamber, and the lasers are interfered by a to-be detected gas and return to the optical-path circuit module for analysis, and are converted into electrical signals which are processed by the portable gas detection apparatus for uploading and alarming. The optical fiber sensor comprises an outer filter screen, the open-type gas chamber and the multiple pairs of lens reflectors.

Description

Technical field: [0001] The patent of the invention relates to the application of optical fiber sensing technology in the field of safety detection and monitoring of flammable, explosive, toxic and harmful gas concentrations in coal mines, non-coal mines, mining and smelting, oil depots, oil tanks, and petroleum refining and chemical industries. Background technique: [0002] Currently at home and abroad, regardless of coal mine methane (CH 4 ), carbon monoxide (CO) gas monitoring, non-coal mining and smelting carbon monoxide (CO), carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), sulfur dioxide gas (SO 2 ), oil tank hydrocarbons, alkanes, diesel mixed gas, petroleum refining industry CH 4 , CO, CO 2 、H 2 Catalytic combustion sensors and infrared sensors are basically used for concentration detection of flammable, explosive, toxic and harmful gases that exist in the working environment such as S and NO. [0003] Catalytic combustion sensor is powered on, the temperatur...

AI Technical Summary

Problems solved by technology

[0003] Catalytic combustion sensors work with power on, high temperature (400-500°C), are greatly affected by ambient temperature and humidity, need to be adjusted every week, the catalytic element in the sensor is prone to poisoning and failure, and the service life does not exceed 12 months; Infrared sensors Affected by the ambient temperature and humidity, the work is unstable and cannot be accurately alarmed. It is usually used as an auxiliary qualitative monitoring

Both types of sensors need to be energized and consume a lot of power. Due to the requirements of fire protection and explosion protection, they cannot be widely used underground, and the fear of leakage of sensors and transmission cables in oil depots also limits their wide application.

[0004] In view of the technical defects, application limitations, and inadequate monitoring of traditional sensors, domestic coal mine gas explosions, oil storage, and refining and chemical enterprises often have large-scale fires, and non-coal mines have toxic and harmful gas poisoning and other vicious accidents, which have caused great harm to life and property. loss

Images