User`s manual

December 2003
10-10 Diagnosis and Troubleshooting
Pipe Problems
Improper pipe conditions and/or flowcell installation can cause
problems with measurement of the fluid flow. Check the items
below if you suspect this class of problem. Contact GE
Panametrics if you cannot solve pipe-related problems.
1. THE INSIDE OF THE PIPE OR FLOWCELL MUST BE
RELATIVELY CLEAN. Excessive build up of scale, rust, or
debris will interfere with flow measurement. Generally, a thin
coating or a solid well-adhered buildup on the pipe wall will
not cause problems. Loose scale and thick coatings (such as
tar or oil) will interfere with ultrasound transmission and may
result in incorrect or unreliable measurements.
2. THE FLOWCELL ORIENTATION MUST NOT ALLOW
SEDIMENT OR GAS ENTRAPMENT AT THE
TRANSDUCER LOCATIONS. Sediment or gas trapped in
the transducer ports for wetted transducers, or at the
transducer locations for clamp-on transducers, will interfere
with flow measurement. Realignment of the flowcell or
transducers often cures these problems. In some cases
different transducers may be used that protrude into the flow
stream.
3. THE PIPE OR FLOWCELL DIMENSIONS MUST BE
ACCURATE. The accuracy of your flow measurements will
be no better than the accuracy of your programmed pipe or
flowcell dimensions. If GE Panametrics did not supply your
flow cell, the dimensions you program must be consistent with
the required flow accuracy. Check your pipe for wall
thickness, diameter, dents, eccentricity, weld deformity, and
straightness.