Clamp-On Transducer Problems - GE AquaTrans AT868 User Manual

Clamp-on Transducer
Problems
Diagnostics
1. POOR COUPLING TO PIPE: Clamp-on transducers must be in
close contact with the pipe. Make sure the pipe wall is 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; therefore; transducer alignment is critical to
assure that the beam can travel from one transducer to the other
without undue attentuation. 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.
4. PHYSICAL DAMAGE: Transducers may be physically damaged by
dropping them onto a hard surface or striking them against another
object. Usually the connector on the transducers is the part that is
damaged, as it is the most fragile. Minor damage may be repaired
by carefully bending the connector back into shape. If the
connector cannot be repaired, replace the transducers.
IMPORTANT:
Transducers must be replaced in pairs. Refer to
Chapter 2, Programming Site Data, to program the
new transducer data into the meter.
5. CYCLE SKIP CONDITION: A cycle skip is usually caused by a
distorted or altered signal due to poor couplant, bad wall or
unusual fluid disturbances. To resolve a cycle skip, recouple both
transducers with proper couplant. Check your couplant for
temperature ranges. In addition, make sure the pipe wall is free of
paint and rust.
Contact the factory if you cannot solve a transducer-related problem.
September 2004
6-9