Uncertainty In Flow Rate For A Non-Insulated Meter - GE Measurement Sentinel LCT4 User Manual

Chapter 7. Troubleshooting

7.7 Uncertainty in Flow Rate for a Non-Insulated Meter

Dimensional compensation considers the effect on the geometrical dimensions of the meter due to the material thermal
expansion or contraction. The fluid temperature inside of the meter is measured and used for this purpose. Under severe
ambient conditions, such as –40°C in winter, the fluid temperature can be very different, by up to 10°C, from the actual
wall temperature. This will cause about a 0.04% error in the flow rate measured. Figure 64 below indicates that the
errors increase as the temperature difference between the fluid and the ambient for both insulated and non-insulated
meters. For non-insulated meters at large temperature differences, the error is about one order higher than that for
insulated meters. Therefore for applications in severe weather conditions, it is recommended that the meter be insulated
to ensure the meter accuracy.
0.05
0.04
0.03
0.02
0.01
-0.01
-0.02
Figure 64: Example of Flow Error at Various Temperature Differences
132
Meter with insulation
Meter without insulation
Carbon Steel meter with insulation
Carbon Steel meter without insulation
0
-40 -20 0
Temperature Difference between Fluid and Ambient (deg C)
20 40 60 80 100 120
Sentinel™ LCT4 User's Manual