Density Measurement Problems - Emerson Micro Motion SGM Series Configuration And Use Manual

14.7

Density measurement problems

Table 14-3: Density measurement problems and recommended actions
Problem Possible causes
Erratic density reading •
•
•
•
•
•
•
•
•
•
Inaccurate density •
reading •
•
•
•
Density reading too •
high
•
•
Density reading too •
low
•
Configuration and Use Manual
Normal process noise
Line pressure too low
Flow rate too high
Pipe diameter too small
Condensation or deposition on the vibrat-
ing element or the internal walls of the cyl-
inder
Contaminants or suspended solids in the
process gas
Vibration in the pipeline
Leakage from the reference chamber
Malfunction of the pressure control valve
Erosion or corrosion
Inaccurate temperature measurement
Incorrect calibration factors
Leakage from the reference chamber or in-
to the reference chamber
Condensation or deposition on the vibrat-
ing element or the internal walls of the cyl-
inder
Contaminants or suspended solids in the
process gas
Condensation or deposition on the vibrat-
ing element or the internal walls of the cyl-
inder
Leakage from the sample path into the ref-
erence chamber
Corrosion, dents, scratches, or other dam-
age to the cylinder
Leakage from the reference chamber to
the atmosphere
Leaks in the pipework or fittings
Recommended actions
• Check your process conditions.
• Increase the density damping value.
• Reduce the flow rate.
• Ensure that line pressure or sample pres-
sure meets installation requirements.
• Increase back pressure to minimize bubble
formation.
• Minimize vibration in the pipeline.
• Check the coalescing filter. See
Section 14.21.
• Check for leakage. See Section
• Increase the pipe diameter.
• Install a flow control method (bypass, flow
chamber, expander, etc.).
• Perform Known Density Verification.
• Verify the temperature reading from the
RTD (on-board temperature sensor).
• Verify the temperature reading from the
external temperature device, if applicable.
• Check the coalescing filter. See
Section 14.21.
• Increase the flow rate.
• Install a thermal insulation jacket.
• Verify the calibration factors.
• Ensure that the cylinder is positioned cor-
rectly.
• Perform Known Density Verification.
• Check for leakage. See Section
• Check the coalescing filter. See
Section 14.21.
• Check for leakage. See Section
• Replace the meter.
• Check for leakage. See Section
Troubleshooting
14.20.
14.20.
14.20.
14.20.
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