Siemens SITRANS DS III series, Compact Operating Instructions

Page: 19 / 288

SITRANS P, DS III series (7MF4.33.. 7MF4.34.. 7MF4.35..)
A5E03434631-02, 12/2012
17
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.
)XOOVFDOHYDOXH
6WDUWRIVFDOHYDOXH
0D[LPXPOHYHO
6WDWLF
SUHVVXUH
K
2
K
8
*DVILOOHGORZ
SUHVVXUHOLQH
7UDQVPLWWHU
UHIHUHQFHOLQH
Measurement assembly on a closed container (no or little
condensate separation)
Formula:
Start-of-scale value: Δp
MA
= ρ · g · h
U
Full-scale value: Δp
ME
= ρ · g · h
O
h
U
Lower filling level Δp
MA
Start of scale value
h
O
Upper filling level Δp
ME
Full-scale value
p Pressure ρ Density of the measured medium in the
container
g Acceleration due to gravity
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.
'
-
K
2
K
8
)XOOVFDOHYDOXH
6WDUWRIVFDOHYDOXH
0D[LPXPOHYHO
6WDWLF
SUHVVXUH
&RQVWDQW
FRPSDULVRQ
OHYHO
/LTXLGILOOHG
ORZSUHVVXUHOLQH
7UDQVPLWWHU
UHIHUHQFHOLQH
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')