Table of Contents
Advertisement
February 2009
Transducer Problems
4-6
The most common clamp-on transducer problems are listed below:
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 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. EXCESS COUPLANT
Clamp-on transducers must be in intimate contact with the pipe. If
there is too much couplant, it may prevent the transducer from
making that contact.
3. 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 follow exactly the instructions that came with your
transducers and clamping fixture. Also, be sure that the transducer
spacing agrees with the calculated spacing (as a function of
soundspeed).
4. 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.
5. PHYSICAL DAMAGE
Transducers may be physically damaged by dropping them onto a
hard surface or striking them against another object. The connector on
the transducer is usually the part that is damaged. Minor damage may
be repaired by carefully bending the connector back into shape. If the
connector cannot be repaired, replace the transducers. After
replacement, the flowmeter parameters should be checked (see
Programming Site Data, Chapter 1 of the Programming Manual, or
Chapter 3 of the Startup Guide).
Contact the factory if you cannot solve a transducer-related problem.
Troubleshooting
Advertisement
Table of Contents
