Ultrasonic flowmeters are
relatively new to the market. They were first introduced for industrial use in 1963 by Tokyo Keiki
in Japan. In 1972, Controlotron became the first U.S. manufacturer to market ultrasonic flowmeters in the United States.
In the late 1970s and early 1980s, both
U.S.-based Panametrics (now GE Panametrics) and the French Ultraflux experimented with the use of ultrasonic flowmeters to measure gas flow.
flowmeters were not well understood, and were sometimes misapplied.
It was not until the 1990s that ultrasonic flowmeters began to be widely used for industrial
improvements expand use
over the last two
decades have continued to expand ultrasonic meter use.
Advances in transit time technology
in particular have broadened the types of liquids that can be measured.
Improvements in electronic processing technology means many transit time meters today
to handle liquids containing some impurities. Because of improvements in electronic processing technology, transit time meters are
better able to handle fluids that are not completely clean. Transit time flowmeters
can now be used for applications that could previously only be handled by Doppler
flowmeters. These improvements have also increased the accuracy of ultrasonic meters, which
has led to a broader use in a wider variety of conditions.
on these topics:
Transit time meters send two ultrasonic signals across a pipe at an
angle and tracks the time the signal takes to cross to the other side. They
are distinguished according to the number of “paths” they
have. Multipath ultrasonic meters have three or more paths. By using more than one path, the flowmeter
measures flow at more than one location in the flowstream, leading to greater accuracy.
Some ultrasonic flowmeters now have up to 18 paths.
flowmeters also send an ultrasonic signal across a pipe but rely on
measuring frequency shifts caused by particles in the flowstream. Doppler ultrasonic flowmeters are used with dirty liquids or slurries. They are not used to measure gas flow.
Meter of choice for
In 1998, the American Gas Association (AGA) approved the use of ultrasonic flowmeters for custody transfer applications. Since that time, suppliers have researched multipath meters and brought out new products.
Ultrasonic meters have become
a top meter of choice for custody transfer of natural gas. Their large
diameter makes them a natural choice for the large line sizes required for transporting natural gas over
long distances, giving them an advantage over Coriolis meters.The high accuracy and reliability of
the multipath ultrasonic meters used for this purpose gives them an advantage over the DP
flow and turbine meters they compete against for this application.
Multipath flowmeters have been especially important
for measuring natural gas flow. Suppliers such as Daniel (now an Emercon
brand), Elster (now Honeywell Elster) and TechnipFMC have introduced four-path, five-path, and six-path transit time meters, respectively, to
measure natural gas flow. The market for inline ultrasonic meters for custody transfer of natural gas is one of the
fastest growing niches in the entire flowmeter market.
about New Technology Flowmeters:
Most manufacturers target liquid petroleum ultrasonic applications
Full-bore design is an important technical characteristic, as throughput is not diminished by obstructions in the liquid fluid flow.
Inline ultrasonic flowmeters are certified for use in liquid custody transfer
applications and now include features that minimize measurement uncertainty, reduce the potential for process
downtime, and are able to identify upstream blockages or abnormal flow profiles in real time.
These features are very beneficial to efficient and economical petroleum liquids production
Caldon (now part of Schlumberger/Cameron) and KROHNE have introduced ultrasonic flowmeters for
custody transfer of petroleum liquids.
Another important application for ultrasonic flowmeters is check
metering -- verifying another flowmeter's readings. Some clamp-on meters are used for this
purpose since they can be conveniently moved from one meter to another. (Clamp-on
technology is unique to ultrasonic meters.) Inline ultrasonic flowmeters
are also used for check metering.
further information on ultrasonic flowmeters, including our detailed market reports,
please see www.flowultrasonic.com.