The GE Panametrics AquaTrans AT868 ultrasonic flow meter
combines state-of-the-art flow measurement capability with a
low-cost transmitter package that can be installed right at
the process measurement point. The AquaTrans AT868 is designed
specifically for water and wastewater applications in full
pipes. Fluid types include acoustically conductive fluids,
such as most clean liquids and many liquids with entrained
solids or gas bubbles.
The all-digital AquaTrans AT868 has no moving parts and
requires minimal maintenance. The AT868 has an onboard
microprocessor, which uses patented Correlation Transit-Time™
technology for long-term, drift-free operation. Automatic
adjustment to changing fluid properties and dynamically
configured operating software simplify programming. An
optional second channel gives the AquaTrans AT868 the ability
to measure flow in two pipes or average two paths on the same
pipe for increased accuracy. Simple setup and installation
make the AquaTrans AT868 your complete ultrasonic flow
metering system.
Choice of Wetted or Clamp-On Transducers
Ultrasonic flow transducers are classified as either wetted
or non-wetted (clamp-on). Clamp-on transducers are clamped
onto the outside of the pipe and never come into contact with
the process fluid. Wetted transducers are mounted into the
pipe or flowcell in direct contact with the process fluid.
Clamp-on transducers offer maximum convenience, flexibility,
and a low installation cost compared to traditional flow
metering technologies. With proper installation, wetted
transducers provide maximum accuracy (better than 1% of
reading) in most applications.
Transit Time Flow Measurement Technique
The transit time technique uses a pair of transducers with
each transducer sending and receiving coded ultrasonic signals
through the fluid. When the fluid is flowing, signal
transit-time in the downstream direction is shorter than in
the upstream direction; the difference between these transit
times is proportional to the flow velocity. The GE Panametrics
AquaTrans AT868 measures this time difference and uses
programmed pipe parameters to determine flow rate and
direction.
