Siemens SITRANS DS III Series Compact Operating Instructions page 19

Assembly on a closed container
When taking measurements in a closed container without or with little condensate formation, the negative pressure line is
not filled. Lay the line in such a way that pockets of condensate do not form. Install a condensation container if required.
Measurement assembly on a closed container (no or little
condensate separation)
h Lower filling level
U
h Upper filling level
O
p Pressure
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. You can cut off the device using the
dual pneumatic block 7MF9001-2.
Measurement assembly on a closed container (strong condensate
formation)
SITRANS P, DS III series (7MF4.33.. 7MF4.34.. 7MF4.35..)
A5E03434656-02, 12/2012
Δp Start of scale value
MA
Δp Full-scale value
ME
ρ Density of the measured medium in the
container
g Acceleration due to gravity
'
-
Formula:
Start-of-scale value: Δp
Full-scale value: Δp
ME
Formula:
Start-of-scale value:
Δp = g · (h
MA U
Full-scale value:
Δp = g · (h
MA O
= ρ · g · h
MA U
= ρ · g · h
O
· ρ- h · ρ')
V
· ρ- h · ρ')
V
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