User`s manual

December 2003
10-8 Diagnosis and Troubleshooting
Flowcell Problems
Flowcell problems fall into two categories: fluid problems and
pipe problems. Read the following sections carefully to determine
if such problems exist.
Fluid Problems
Most fluid-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 fluid-
related problem.
Certain fluid properties may prevent proper flow measurement.
Some fluid properties that cause problems are listed below.
1. THE FLUID MUST BE HOMOGENOUS, SINGLE PHASE,
RELATIVELY CLEAN, and FLOWING STEADILY. Solid
particles and gas bubbles absorb and disperse ultrasound.
Although, in some cases, solids and gases have little effect on
the operation of the TransPort, excessive amounts will prevent
ultrasound transmission through the fluid and interfere with
proper flow measurement. Temperature gradients may also
cause a problem.
2. THE FLUID MUST NOT CAVITATE NEAR THE
FLOWCELL. Fluids with a high vapor pressure may cavitate
near or in the flowcell. This causes problems resulting from
gas bubbles in the fluid. Cavitation can usually be controlled
through proper installation design.
3. THE FLUID MUST NOT ATTENUATE ULTRASOUND
EXCESSIVELY. Some fluids, particularly those that are very
viscous, absorb ultrasound energy. In these cases an “E1” will
display on the screen to indicate that the ultrasonic signal is
not of sufficient strength for reliable measurements.