Panametrics Sentinel LCT, User Manual

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Sentinel LNG User’s Manual 203
Chapter 9. Troubleshooting
9.4.2 Pipe Problems
Pipe-related problems may result from improper choice in meter location or errors in programming. The following
may result in problematic installations:
1. The collection of material at the transducer location(s).
Accumulated debris at the transducer location(s) will interfere with transmission of the ultrasound signals.
Choose an installation point for the meter where solid particles will not settle into the transducer ports. Refer to
Chapter 2, Installation, for more details on proper installation practices.
2. The inside of the pipe must be relatively clean.
Excessive build up of scale, rust or debris will change the inner dimensions of the pipe and will result in
inaccuracies in the calculation of the flow from the velocity measurement.
9.5 Transducer Problems
The
Sentinel LNG
transducers are rugged, reliable devices that do not come into contact with the process fluid. An
engineered epoxy with the appropriate physical and acoustic properties holds the transducer in place. If erratic or
inaccurate readings can be tracked to a problem with a transducer or transducers, or if one is physically damaged,
the Panametrics Sensing field service team has the appropriate methods and tools to properly replace the
transducer to maintain the accuracy of your flow meter system. Consult your local representative to schedule this
service.
9.5.1 Clamp-on Transducer Problems
In certain special applications, the SEN898 display package may be used with clamp-on transducers. This section
covers these applications.
1. 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.
2.
PHYSICAL DAMAGE:
Transducers may be physically damaged by dropping them onto a hard surface or striking
them against another object.
IMPORTANT: Transducers must be replaced in pairs. Refer to Chapter 3, Operation, to program the new transducer
data into the meter.
3.
CYCLE SKIP CONDITION
: A cycle skip is usually caused by a distorted or altered signal due to unusual fluid
disturbances.
Contact the factory if you cannot solve a transducer-related problem.