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Diagnosis and Troubleshooting 10-9
April 2004
Flowcell Problems
Flowcell problems fall into two categories: gas problems and pipe
problems. Read the following sections carefully to determine if
such problems exist.
Gas Problems
Most gas-related problems can be solved by proper design of the
flowmeter installation and the proper choice of transducer
frequency. Contact GE Panametrics if you cannot solve a gas-
related problem.
If the physical installation of the system meets the recommended
specifications, it is possible that the gas itself may be preventing
accurate flow rate measurements. The gas being measured must
meet the following requirements:
1. THE GAS MUST BE HOMOGENOUS, SINGLE-PHASE
AND RELATIVELY CLEAN. Although a low level of
entrained particles may have little effect on the operation of
the TransPort, excessive amounts of solid or liquid particles
will absorb or disperse the ultrasound signals. This
interference with the ultrasound transmissions through the gas
will cause inaccurate flow rate measurements. In addition,
temperature gradients in the gas flow may result in erratic or
inaccurate flow rate readings.
2. THE GAS MUST NOT EXCESSIVELY ATTENUATE
ULTRASOUND SIGNALS. Some gases (i.e., high-purity
carbon dioxide, hydrogen, helium, etc.) readily absorb
ultrasound energy. In these cases an “E1” will appear on the
screen to indicate that the ultrasonic signal is insufficient for
reliable measurements.