Relative humidity modifying is introduced into measurement system for gas in the pipeline and a humidity sensor is used to transforme the signals of relative humidity.Moreover

on-line measurement system and model are gotten through a fitting formula about water vapour saturated pressure in the gas at different temperature based on function chain neural network

which would greatly simplify the software of measurement about gas flow in the pipeline and would quickly realize on line measurement about gas flow in the pipeline at the design range of flowmeter.The application results show that the measurement system error for gas flow in the pipeline is ±0.7 %.