Design and Test of Thermal Flowmeter Based on Constant Power
To solve the problem of temperature drift of thermal flowmeter,the structure of thermal flowmeter in constant power mode was proposed,and its digital calibration method was studied.Compared with conventional thermal flowmeters,an environ-mental probe was added,which was embedded in the fluid pipe wall.The sensors were insulated from each other.The voltage sig-nal measured by the environmental probe and the temperature sensor was calibrated digitally in real time.The flowmeter was test-ed by the sonic nozzle gas meter inspection device.The test results show that the error rate is controlled within 0.5%in the flow range of 0.016~0.25 m3/h,and the error rate is controlled within 1.0%in the flow range of 0.25~6 m3/h,and the temperature drift phenomenon is effectively improved.