Siemens SITRANS 7MF03.0 - Page 27

When taking measurements in a closed container with strong condensate formation, you must
fill the negative pressure line (mostly with the condensate of the measured medium) and install
a condensate pot. Lock the device using the dual pneumatic block 7MF9017-..A.
'
-
K
2
K
8
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K
Y
Measurement assembly on a closed container (strong condensate
formation)
Formula:
Start of scale value:
Δp
MA
= g · (h
U
· ρ - h
V
· ρ')
Full-scale value:
Δp
MA
= g · (h
O
· ρ - h
V
· ρ')
h
U
Lower filling level Δp
MA
Start of scale value
h
O
Upper filling level Δp
ME
Full-scale value
h
V
Gland distance ρ Density of the measured medium in the
container
p Pressure ρ ' Density of fluid in the negative pressure
line corresponds to the prevailing tem‐
perature there
g Acceleration due to gravity
The process connection on the negative side is a female thread
1
/
4
-18 NPT or an oval flange.
Lay the line for the negative pressure using a seamless steel tube 12 mm x 1.5 mm.
Installing/mounting
3.3 Installation (level)
SITRANS P320/P420 (mA/HART)
Compact Operating Instructions, 06/2018, A5E38874562-AA 27