Accuracy is an important index of measuring meter. For the measurement of Transit-Time Ultrasonic Flowmeters, its error sources mainly come from the following aspects:
1. The effect of machining accuracy and temperature variation on mechanical dimension.
The machining accuracy and temperature stability of pipe diameter, path length and other mechanical parameters, which have a direct impact on flow measurement. During the measurement, they vary with the temperature.
2. The effect of temperature variation on flow velocity.
The propagation velocity of ultrasonic wave increases with the increase of fluid temperature, which will bring errors to the measurement.
3. The variation of echo waveform and amplitude bring errors.
This change will change the timing comparison point of the binarization circuit of ultrasonic flowmeter and cause waveform error.