Multi-component Gas Concentration Detector Based On Electrochemical Sensor

With the progressed of technology and the developed of energy industry in oil and coal, the flammable, explosive, toxic gas' species are increasing and its scope of application is also expanding. Therefore, the detection of these gases is very important. The traditional gas monitor aims at one kind of gas, but along with the development of instrument multifunction, the demand for gas monitor which could monitor many kinds of gas was gradually appear. The thesis has designed a multifunction gas monitor to monitor and record the carbon monoxide, hydrogen, oxygen and combustible gas (methane) concentration in real-time.In this design, the instrument detects carbon monoxide, hydrogen, oxygen and combustible gas (methane) content rapidly and accurately by four kinds of gas-sensitive electrochemical sensors mentioned above, and through the LCD displays the gas concentration of each component. When the gas concentration reaches a certain threshold, it will give off acousto-optic alarm. To enhance practical value, the system is also designed a human interface with the computer, communication port with computer, battery power detection device, gas pump module. In order to achieve the above functions, system should have gas detection sensor, signal conversion and adjust module, MCU, LCD, input keyboard, acousto-optic alarm module, battery power detection module and gas pump control module.The core of this control system is C8051F005 MCU. It converts the gas sensor signal, battery power signal to electrical signals output respectively by A/D. While the detected gas concentrations are over the warning level, light and beep alarm signals will be generated. The acquired data are saved into 24C256 in case of losing data due to power break. The saved data can be anew transferred to PC through a Bluetooth module. Some exterior keys are also installed on the panel to set the alarm value. In addition, the power consumption of the instruments is evaluated and methods to further reduce it are discussed.By testing at laboratory, the system has strong points of small volume, low power consumption, easy maintenance, strong ability of data processing and anti-interference as well as high testing precision.