Research And Development Of Thermal Gas Mass Flowmeter

World changes with the progress of science and technology, so does the flowmeter world. Thermal type gas mass flowmeter(TMF), as a member of the gas flowmeters, is famous for its to measure small flow rate and big diameter flow, also changing with the changes of The Times. TMF also has characteristics such as simple structure, wide measure range, high reliability, good stability, good reproducibility and controlled cost, and now has been widely used in various fields in the gas flow measurement, Such as oxygen, natural gas, coal gas, car tail gas, industrial waste gas and mix gas.Through market research and reviewing related literature, we know that the application prospect of gas meter is widespread, and is becoming more and more essential to every field at home and abroad. Being guided by the market requirement, choosing the Platinum thermistor with high sensitivity as sensor, selecting the PIC18F4580 belonging to Microchip as the core unit, following the design thought of modular hardware, combining with hardware and software, we develop a high-performance TMF Successfully. The precision of TMF reaches±1 %, and the TMF is reliable and stable. Beside, clear LCD module ensures the real-time flow and cumulative flow online display and it is convenient to read; Reserved RS- 485 serial port is convenient for communicating flow meter with the upper machine, and used to have calibration of standard flow, Settings of parameters such as pipe diameter, gas concentration, and remote monitoring. The device has a 4-20 mA output channel which is convenient for remote monitoring and the industrial control.After the flowmeter prototype is designed and manufactured, an experimental platform is designed to demarcate and test this prototype, and the prototype is tested on the platform. Through the analysis of experimental data obtained, indicates that the designed TMF has excellent performance in the aspect of precision, error, stability and reliability. It can be improved according to the different needs of the market later and turns research achievements into production.