User`s manual

Diagnosis and Troubleshooting 10-11
December 2003
Pipe Problems (cont.)
4. THE PIPE SURFACES SHOULD BE SMOOTH (FOR
CLAMP-ON). When using clamp-on transducers, both the
inside and the outside of the pipe at the transducer locations
must be smooth. If the pipe is extremely rough, the ultrasonic
signal will be scattered by the rough surface, and will not be
received by the flowmeter, preventing flow measurement.
5. THE PIPE MUST ALLOW ULTRASOUND TO PASS
THROUGH (FOR CLAMP-ON). Some pipe materials or
linings such as Fiberglass (or generic fiber reinforced pipe),
Teflon, and polyethylene, absorb ultrasound and may cause
problems in clamp-on applications. Pipes with extremely thick
walls or high OD to ID ratios may also present difficulties.