There are three types of speedometers for measuring natural gas, which are vortex flow meters, ultrasonic flow meters and turbine flow meters. This article discusses vortex flowmeters, and subsequent articles will discuss the pros and cons of other speedometers.
The vortex flowmeter is a volumetric flowmeter that measures the volumetric flow rate of a gas, vapor or liquid, the volumetric flow rate of a standard condition, or the mass flow rate according to the principle of Karman vortex. It is mainly used for flow measurement of industrial pipeline medium fluids, such as gas, liquid, steam and other media.
It is characterized by small pressure loss, large measuring range and high precision. It is almost unaffected by parameters such as fluid density, pressure, temperature and viscosity when measuring the volume flow rate. No moving mechanical parts, so the reliability is high and the maintenance is small. Instrument parameters can be stable for a long time. The vortex flowmeter uses a piezoelectric stress sensor with high reliability and can operate in the operating temperature range of -20 °C to +250 °C. There are analog standard signals and digital pulse signal outputs, which are easy to use with digital systems such as computers. It is a relatively advanced and ideal measuring instrument.
This article is part of a continuous series exploring various types of gas flow meters, including mass flow meters, volumetric flow meters, speed meters and inferential flow meters. You may also be interested in 4 things before choosing gas flow meter technology.
A speedometer is a meter that measures the velocity of a gas flowing through a meter. These meters use the formula for the gas flow rate X cross-sectional area of the flow meter to determine the volumetric gas flow.
Q (volume flow rate) = v (flow rate) × A (cross-sectional area)
The vortex flowmeter for gas flow is accurate and reliable and can be used to measure gas distribution and transmission, gases in industrial equipment and business operations. The vortex flowmeter is a traditional airflow technology that remains the actual and favorite choice for natural gas flow measurement. It is approved for custody transfer of natural gas and is used for billing for commercial buildings and factories, in this application competing with positive displacement (PD) meters. Vortex flowmeters excel at measuring high-speed flow and stabilizing fluids, while PD flowmeters offer better low-speed applications in 1.5-10 inch lines. Vortex flowmeters cannot be used to measure steam flow.
Vortex flowmeters are a common choice for natural gas flow. It is much cheaper than an ultrasonic flow meter and costs less than Coriolis as the line size increases. When the application requires several differential pressure gauges instead of a vortex flowmeter, the differential pressure gauge can also save a lot of cost. Users often don't want to invest in new technology and are more likely to use familiar, proven products - vortex flowmeters.
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After proper calibration, the vortex flowmeter is comparable to the accuracy of a multi-channel ultrasonic flowmeter.
One disadvantage of vortex flowmeters is that they cause a pressure drop, which is an unavoidable consequence because the flowmeter is designed to place the rotor in the airflow. Some manufacturers have solved the pressure loss problem with a two-way vortex flowmeter (SM-RI-2).
Another disadvantage is that they have moving parts, and while some manufacturers have improved bearings that make the meter more reliable, moving parts are still a disadvantage of vortex flow meters.
Conventional vortex flowmeters also require manual lubrication and are traditionally unidirectional, but as noted above, two-way flow meters and self-lubricating models have been introduced.
Finally, vortex flowmeters have limitations at low flow rates and may not rotate if the gas current drops below 15% of the flowmeter's nominal flow rate.
Energy metering is an important means of scientifically managing energy, achieving energy conservation and reducing consumption, and improving economic efficiency. Flow meters are an important part of energy metering. Water, artificial gas, natural gas, steam and oil use a very large number of flow meters, which are indispensable tools for energy management and economic accounting.