Ultrasonic Flow Meters in Gas Flow Measurement – Application limitations & Best Practices
All flow measurement technologies have their individual limitations that impact on flow measurement accuracy. It is therefore important for engineers and technicians who use any flow measurement technology to consider the limitations of the flow meter proposed for use in a particular application before installation.
Below are the key factors which affect flow measurement accuracies in Ultrasonic meters used in custody applications for gas measurement:
1. Noise
2. Accumulation of Dirts and Liquids
3. Profile Distortions
Noise in Ultrasonic Flow Measurement
Ultrasonic flow measurement depends on accurate transit time measurement of sonic pulses. Noise inside the pipe work especially from fittings – valves, tees etc- can interfere with the detection of sonic pulses if the noise is of coincident frequency with the meter’s transducers and drown out the sonic pulses if it is sufficiently high in amplitude. Once pulses are drowned out, detection and therefore pulse transit time measurement becomes impossible and flow measurement practically stops.
Best Practices that Reduce Meter Errors due to Noise
1. Install Ultrasonic meters upstream of regulating devices
2. Locate the noise attenuating elements between meter and the noise source
3. Consult the meter manufacturer for meters of alternative frequency
Below are the key factors which affect flow measurement accuracies in Ultrasonic meters used in custody applications for gas measurement:
1. Noise
2. Accumulation of Dirts and Liquids
3. Profile Distortions
Noise in Ultrasonic Flow Measurement
Ultrasonic flow measurement depends on accurate transit time measurement of sonic pulses. Noise inside the pipe work especially from fittings – valves, tees etc- can interfere with the detection of sonic pulses if the noise is of coincident frequency with the meter’s transducers and drown out the sonic pulses if it is sufficiently high in amplitude. Once pulses are drowned out, detection and therefore pulse transit time measurement becomes impossible and flow measurement practically stops.
Best Practices that Reduce Meter Errors due to Noise
1. Install Ultrasonic meters upstream of regulating devices
2. Locate the noise attenuating elements between meter and the noise source
3. Consult the meter manufacturer for meters of alternative frequency
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