GE DigitalFlow GC868, Руководство по обслуживанию

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Diagnostics 3-5
April 2008
Gas Problems (cont.)
2. The gas must not excessively attenuate ultrasound signals.
Some gases (i.e., high-purity carbon dioxide, hydrogen, etc.)
readily absorb ultrasound energy. In such a case, an
E1
error code
message will appear on the display screen to indicate that the
ultrasonic signal strength is insufficient for reliable measurements.
3. The gas sound speed must not vary excessively.
The Model GC868 will tolerate relatively large changes in the gas
sound speed, as may be caused by variations in gas composition
and/or temperature. However, such changes must occur slowly.
Rapid fluctuations in the gas sound speed, to a value that is
considerably different from that programmed into the Model
GC868, will result in erratic or inaccurate flow rate readings.
Refer to Chapter 2,
Initial Setup , of the Startup Guide and make
sure that the appropriate sound speed is programmed into the
meter.
Pipe Problems
Pipe-related problems may result either from a failure to observe the
installation instructions, as described in the
Startup Guide , or from
improper programming of the meter. By far, the most common pipe
problems are the following:
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. As a result, accurate
flow rate measurements are not possible. Realignment of the
flowcell or transducers often cures such problems. Refer to
Chapter 1,
Installation , of the Startup Guide for more details on
proper installation practices.
2. Inaccurate pipe measurements.
The accuracy of the flow rate measurements is no better than the
accuracy of the programmed pipe dimensions. For a flowcell
supplied by GE, the correct data will be included in the
documentation. For other flowcells, measure the pipe wall
thickness and diameter with the same accuracy desired in the flow
rate readings. Also, check the pipe for dents, eccentricity, weld
deformity, straightness and other factors that may cause inaccurate
readings. Refer to Chapter 2,
Initial Setup , of the Startup Guide for
instructions on programming the pipe data.