Siemens SITRANS P - Manual (Page 185)

SITRANS P measuring instruments for pressure
Remote seals
Measuring setups without remote seals
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■
Overview
Notes
• For the separation layer measurement, the separation layer
has to be positioned between the two spigots.
Also you must make sure that the level in the container is al-
ways above the top spigot.
• When measuring density, make sure that the level of the me-
dium remains constant. The level should be above the top
spigot
■
Dimensional drawings
Pressure transmitters for differential pressure, for flanging
Measuring setups for open containers
r
+
Ho
Hu
Level measurement
Start-of-scale: p
MA
= r · g · H
U
Full-scale: p
ME
= r · g · H
O
Legend
p
MA
Start-of-scale value to be set
p
ME
Full-scale value to be set
r Density of medium in vessel
g Local acceleration due to gravity
H
U
Start-of-scale value
H
O
Full-scale value
Full-scale value
Start-of-scale value
r
r
H
u
2
1 H o
+
Separation layer measurement
Start-of-scale: p
MA
= g · (H
U
· r
1
+ (H
O
- H
U
) · r
2
)
Full-scale: p
ME
= r
1
· g · H
O
Legend
p
MA
Start-of-scale value to be set
p
ME
Full-scale value to be set
r
1
Density of heavier liquid
r
2
Density of lighter liquid
g Local acceleration due to gravity
H
U
Start-of-scale value
H
O
Full-scale value
Constant level
= full-scale value
Start-of-scale value
Separation layer
Ho
+
r
Density measurement
Start-of-scale: p
MA
= r
MIN
· g · H
O
Full-scale: p
ME
= r
MAX
· g · H
O
Legende
p
MA
Start-of-scale value to be set
p
ME
Full-scale value to be set
r
MIN
Minimum density of medium in vessel
r
MAX
Maximum density of medium in vessel
g Local acceleration due to gravity
H
O
Full-scale value in m
Constant level
© Siemens AG 2008