FlowTime Clock ...
flowtime is it?
Time displayed is Flowtime.
New Technology Flowmeters
include Coriolis, Magnetic, Ultrasonic, Vortex, and Thermal. Click
on a button to learn more.
For information on Traditional
Technology Flowmeters, which includes Differential
Displacement, Turbine, Open Channel, Variable Area, and Primary Elements,
select Traditional Tech from the listing on the left, or just click here: http://www.TradTechFlow.com.
Information About Ultrasonic Flowmeters
There are two
main types of ultrasonic flowmeters: transit time and Doppler.
A transit time ultrasonic flowmeters has both a sender and a receiver.
It sends two ultrasonic signals across a pipe at an angle: one with the
flow, and one against the flow. The
meter then measures the “transit time” of each signal.
When the ultrasonic signal travels with the flow, it travels faster than
when it travels against the flow. The
difference between the two transit times is proportional to flowrate.
flowmeters also send an ultrasonic signal across a pipe.
Instead of tracking the time the signal takes to cross to the other side,
a Doppler flowmeter relies on having the signal deflected by particles in the
flowstream. These particles are
traveling at the same speed as the flow. As the signal passes through the
stream, its frequency shifts in proportion to the mean velocity of the fluid. A
receiver detects the reflected signal and measures its frequency. The meter
calculates flow by comparing the generated and detected frequencies. Doppler
ultrasonic flowmeters are used with dirty liquids or slurries.
They are not used to measure gas flow.
flowmeters were first introduced for industrial use in 1963 by Tokyo Keiki
(which later became Tokimec) in Japan. Tokimec
is located in Tokyo, Japan. In
1972, Controlotron (Hauppauge, New York) became the first U.S. manufacturer to
market ultrasonic flowmeters in the United States.
In the late 1970s and early 1980s, both Panametrics (Waltham,
Massachusetts) and Ultraflux (Poissy Cedex, France) experimented with the use of
ultrasonic flowmeters to measure gas flow.
Initially, ultrasonic flowmeters were not well understood, and were
sometimes misapplied. Many
technological improvements have been made in the past 10 years, and the
limitations of ultrasonic meters are better understood.
Advances in transit time technology have broadened the types of liquids
that transit time flowmeters can be used on. Many transit time meters today can
handle liquids containing some impurities.