Liquid Controls SP4000 - Manual (Page 65)

62
SP4000 Flow Computer
The DP-Factor describes the relationship between the flowrate and the
measured differential pressure. The flowrate is computed according to one of
the three following equations, depending on the selected flow equation:
Steam (or gas) mass flow:
Liquid volume flow:
Gas corrected volume flow:
M Mass flow
Q Volumetric flow
Q
REF
Corrected volumetric flow
K
DP
DP-Factor
ε
1
Gas expansion factor (Y
1
)
T Operating temperature
T
CAL
Calibration temperature
∆
p Differential pressure
ρ
Density at flowing conditions
K
ME
Meter expansion coefficient x 10 –6
ρ
REF
Reference density
DP FACTOR
6.8
FLOW INPUT
(Continued)
FLOW INPUT
2 •
∆
p •
ρ
1 – K
ME
• (T – T
CAL
)
√
K
DP
ε
1
• •
M =
(2 •
∆
p)
/ρ
(1 – K
ME
• (T – T
CAL
))
√
K
DP
•
Q =
2 •
∆
p •
ρ
(1 – K
ME
• (T – T
CAL
))
√
Q
REF
=
K
DP
ε
1
• •
ρ
REF
•