In part three of this series on natural gas flow meter types, here we discuss the Coriolis flowmeter.
Natural Gas Flow Measurement
Our blog usually explores thermal mass flow meters because that is our business. While our meters serve a variety of applications, there are additional devices that excel in other gas flow measurement areas. For this reason, we occasionally explore other gas meters. The Coriolis meter is used to measure natural gas and is approved for use in custody transfer. While this meter type is used to measure both liquid and gases, this post highlights information pertaining to natural gas.
As the thermal mass flow meter, the Coriolis meter measures gas mass flow and is also known as an inertial flow meter. There has been a trend over the last nine years where many process plants have been replacing their differential pressure (DP) meters with Coriolis meters, even though they are more expensive they are perceived as being a favorable investment. Additionally, there have been significant new product enhancements for Coriolis meters over the last few years which has expanded the meter’s use in larger line sizes.
Coriolis meter provides a direct mass flow measurement based upon the deflection force of a fluid moving through an oscillating tube. For this style meter, the flow is measured by analyzing the changes in Coriolis force of a flowing substance. The mass flowing through a tube creates a force that is proportional to the mass flow rate of that fluid.
The Coriolis flow meter is extremely accurate, has high turndown capabilities, is reliable and as ultrasonic gas meters, they are approved for use in natural gas custody transfer. While approved for fiscal accounting, there has been some reluctance to use them in this capacity. The meters measure mass flow, not volumetric flow, so there is no need for pressure and temperature devices to calculate flow. They also have no internal moving parts, so there is very little maintenance and require very little attention once installed. They excel in line sizes of 2” and less.
Of course, being the most accurate meter on the market comes at a cost, and Coriolis meters bear a high initial expense. Historically this meter type has been inflexible in pipes larger than 4,” however, over the last few years there has been an entry of Coriolis meters for large pipeline sizes, including up to 14.” While this meter type is used to measure gas, they have an easier time measuring liquids over gases due to the low density of gas.
Manufacturers of Coriolis flow meters include Endress+Hauser, FMC Technologies, GE Measurement & Control Solutions (Rheonik), Krohne, Micro Motion and others.
If you are interested in natural gas flow measurement, you may want to review the following meter styles:
- Diaphragm meters
- Rotary meter
- Gas Turbine Meter
- Ultrasonic flowmeters
- Orifice plates
- Thermal mass flowmeter