User`s manual

December 2003
10-14 Diagnosis and Troubleshooting
Clamp-on Transducer Problems
1. POOR COUPLING TO PIPE
Clamp-on transducers must be in intimate contact with the pipe.
The pipe wall must be smooth and generally free of paint. The
couplant material must fill voids between the transducer and the
pipe, and must be firmly coupled or bonded to both the pipe and
the transducer. The pipe and transducer must be clean and dry for
permanent couplant, such as grease or epoxy, to adhere properly.
Enough pressure must be applied to the transducer by its clamp to
hold it firmly against the pipe.
2. MISALIGNMENT
The transducer transmits relatively narrow beams of ultrasound,
and therefore transducer alignment is critical to assure that the
beam can travel from one transducer to the other without undue
attenuation. Be sure to exactly follow the instructions that came
with your transducers and clamping fixtures. Also, be sure that
the transducer spacing agrees with the calculated spacing (S).
3. INTERNAL DAMAGE
Ultrasonic transducers consist of a ceramic “crystal” bonded to
the transducer case. The bond between the crystal and the case
may be damaged by extreme shock and by temperature extremes.
The crystal itself can also be damaged by the same conditions.
The internal wiring can be corroded or shorted if contaminants
enter the transducer housing.