1.3 Recommended sample flow rate
Use the smallest acceptable flow rate for the process gas passing through the meter. This
ensures a sample gas flow rate that is representative of the main flow with regard to the
proportions of different gas constituents.
Micro Motion recommends a gas flow rate of 5 ±1 l/hr (0.176 ±0.35 ft
3
/hr), although a flow
rate between 1 to 10 l/hr (0.035 to 0.35 ft
3
/hr) is acceptable.
At flow rates greater than 10 l/hr (0.35 ft
3
/hr), the density reading can become slightly
unstable and may introduce a small density error. For natural gas with a typical application
density of approximately 0.06 g/cm
3
(60 kg/m
3
), a pressure differential of approximately
1.66 mbar (0.67 in WC) is required to maintain a flow rate of 5 l/hr (0.176 ft
3
/hr) .
Pressure drop through the meterFigure 1-1:
Volume of gas in meter = 40 cm
3
3.5
3
2.5
2
1.5
1
.5
0
0 2 4 6 8 10
Flowrate (lt/hr)
Recommended
operating
flow rate
Volume of gas in meter = 2.44 in
3
1.2
1.0
.8
.6
.4
.2
0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Flowrate (ft
3
/hr)
Pressure drop (mbar)
Pressure drop (inch WC)
Recommended
operating
flow rate
Planning
Installation Manual 3
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