In my ongoing series on natural gas flow meter types, within this post I discuss the gas turbine meter which can be used to measure natural gas in industrial and commercial billing applications.
Natural Gas Flow Measurement
Sage Metering manufactures thermal mass flow meters, and our posts traditionally consider applications for our meters. From time-to-time, however, other meters perform well in different applications. This is why I have reviewed Coriolis meters, diaphragm meters, rotary meters, and ultrasonic meters, and here I discuss turbine flowmeters.
Gas Turbine Meter
The turbine flowmeter is considered one of the main traditional flow meter technologies, along with differential pressure and positive displacement meters. They still are a favorite device used to measure gas flow, particularly for clean, medium-to-high steady flow of low-viscosity fluids. The turbine meter measures volumetric flow based on fluid flowing passed a free-spinning rotor, with each revolution agreeing with a specific volume of fluid. Turbine meters are used for measurement of liquids as well natural gas flow.
The turbine meter has certain cost advantages over other natural gas flow measurement options, particularly those reluctant to invest in new technology. They are also significantly less expensive, particularly in large pipe sizes, to the ultrasonic meter and the Coriolis meter. There are additional cost advantages over DP meters, particularly in applications where a single-turbine meter can replace several DP meters.
The meters have high turndown and accuracy at mid-to-high flow, and medium rangeability at high pressure. Electronic output is also available. Additionally, this natural flow totalizer has reasonable industry acceptance.
Certainly, the turbine meter has moving parts which is always a limitation, and the user needs to consider the cleanliness of the gas. Some turbine meter manufacturers have made improvements to the internal components to minimize these concerns, but having moving parts is still a disadvantage. Other improvements by manufacturers have included reduced pressure drop, bidirectional flow and self-lubrication.
The meter requires initial laboratory flow calibration, and relatively high pressure loss. There is also the chance of damage because of over-speeding the meter.
Turbine Meter Manufacturers
Some of the gas turbine meter manufacturers are Elster-Instromet (American Meter), Emerson Process Management (Daniel), FMC Technologies (INVALCO) and GE (Dresser).