Siemens SITRANS P500, Operating Instructions Manual, Page: 44 / 238

Install
4.6 "Level" installation
SITRANS P500 with HART
44
Operating Instructions, 12/2014, A5E02344528-09
4.6.3.3 Measurement on closed vessels with heavy condensation
When taking measurements in a closed container with strong condensation formation, you
must fill the negative pressure line (mostly with the condensation of the measured medium)
and install a condensation pot. You can shut off the device e.g. using a two-way valve block
7MF9411-5AA.
Formula:
Start of scale value
Δp
MA
= g · (h
U
· ρ - h
V
· ρ')
Full scale value
Δp
ME
= g · (h
O
· ρ - h
V
· ρ')
h
U
Start of scale value Δp
MA
Start of scale value to be set
h
O
Full scale value Δp
ME
Full scale value to be set
h
V
Gland distance ρ Density of the medium in the vessel
p Pressure ρ ' Density of fluid in the negative pres-
sure line, corresponds to the tempera-
ture prevailing there.
g Acceleration due to gravity
Measurement assembly on a closed container:
strong condensation formation
The process connection on the negative side is a female thread
1
/
4
-18 NPT.
Lay the line for the negative pressure using a seamless steel tube 12 mm x 1.5 mm.