Similar to most metering technologies, turbine meters are known to be affected by abnormal flow or abnormal mechanical conditions which can cause bias in flow measurement. These types of flow conditions include blockage at the flow meter or straightening vanes, grime or liquid contamination on the internal meter components, damage to the internal meter components, and pulsation in the flow.
With the introduction of ultrasonic and Coriolis meters for gas applications, the natural gas industry has embraced the concept of meters with embedded diagnostic capabilities. These capabilities allow the...
With the introduction of ultrasonic and Coriolis meters for gas applications, the natural gas industry has embraced the concept of meters with embedded diagnostic capabilities. These capabilities allow the detection of potential problems with the flow behavior or meter condition that may lead to measurement error. Diagnostic measurements also exist for turbine meters. Some turbine meter manufacturers provide techniques for diagnosing proper meter performance through approaches that include unique design attributes (e.g., dual-rotors) or by monitoring the characteristics (shape, timing, etc.) of the pulses produced as blades pass a sensor. Various analog and digital signal analysis methods exist to interpret the output pulse characteristics to determine meter condition attributes such as bent blades and bearing wear. The objective of this research was to assess, through flow testing, the ability of various diagnostic methods to detect abnormal flow and abnormal mechanical conditions for both single and dual-rotor turbine meters. A secondary objective was to determine the amount of flow measurement error that could be present for the various flow conditions that were tested. The approach was to test three different diagnostic methods on a single-rotor and dual-rotor turbine meter at the Metering Research Facility at Southwest Research Institute. The selected diagnostic methods were the Smith MeterTM AccuLERT II from FMC Technologies, TurbinScope from Elster-Instromet, and The Turbo Corrector from Mercury Instruments. Tests were performed under controlled conditions and were designed to determine the ability of the selected diagnostics to detect various levels of flow meter or tube bundle blockage, grime buildup on the rotor or rotor bearings, damage to the rotor, or flow pulsations.