Turbine flow meters have historically provided volumetric total flow and with advancements in electronics technology, flow rate measurements. They are commonly used in hydrocarbon liquid measurements where the fluid lubricates the turbine to help the rotor assembly move freely.
In a Processing Magazine article, Digital Transformation Strategies for Mechanical Flow Instrumentation, Emerson’s Tom Bass highlights their role as simple to operate and maintain, as well as a reliable, cost-effective method for achieving accurate flow measurement.
These devices originally were mechanical devices using gears and rotary counters to measure the turbine revolutions. Tom describes the shortcomings of these mechanical meters.
First, they cannot deliver real-time flow readings and, second, there is no capability to send data to an information-gathering or automation system.
Advancing beyond mechanical counting, electronic signal processing uses a proximity sensor:
…built into the housing wall, capable of sensing every time one of the turbine blades passes by and creates an electronic pulse. A pulse counter totalizes the number of rotations to calculate the accumulated flow volume, effectively replacing the rotary counter. More sophisticated electronics can also compare the rate to a clock and calculate a real-time flow rate.
Advantages of turbine flow meters are that they use:
…advanced materials and electronics to deliver a high degree of durability and accuracy. Stainless steel internal assemblies maximize volume throughput with minimal pressure drop, enabling high flow rates without sacrificing a wide turndown range. Improved electronics use two proximity sensors combined with a durable dual-channel preamplifier to guarantee pulse integrity, avoiding missing or double-counted pulses.
Tom shares how existing mechanical turbine meters can be retrofitted with technologies such as the Rosemount 705 Wireless Totalizing Transmitter that:
…can read pulses from the turbine blades using the existing proximity sensor. With advanced signal processing options, it is possible to capture totalized flow data, average flow rate over a specified period of time, and a current real-time flow rate.
Read the article for more as Tom shares a use case for this technology on injection wells at an oil & gas production site and the improved operator efficiency, improved production, and reduced operating costs the accessibility of this information provided.
Visit the Turbine Flow Meter section on Emerson.com for more on how these devices work and the advantages they provide in flow measurement. You can also connect and interact with other flow measurement experts in the Measurement Instrumentation group in the Emerson Exchange 365 community and/or at the September 23-27 Emerson Exchange conference in Nashville.