Deltabar S PMD70/75 FMD76/77/78

+ –
www.aotewell.com www.fa-market.com info@aotewell.com
Deltabar S
Vacuum applications
For applications under vacuum, Endress+Hauser recommends mounting the pressure transmitter below the
lower diaphragm seal. This prevents a vacuum load of the diaphragm seal caused by the presence of filling oil
in the capillaries.
When the pressure transmitter is mounted above the lower diaphragm seal, the maximum height difference
H1 in accordance with the following illustration must not be exceeded. The maximum height difference is
dependent on the density of the filling oil and the smallest ever pressure that is permitted to occur at the
diaphragm seal on the positive side (empty tank), see the following illustration, on the right.
12.0
Low temperature oil
–
+
– +
H1
Height difference H1 [m]
10.0
8.0
6.0
4.0
2.0
Silicone oil
Vegetable oil
High temperature
oil
Inert oil
0.0
50 100 200 300 400 500 600 700 800 900 1000
Pressure, diaphragm seal positive side [mbar abs ]
P01-FMD7xxxx-11-xx-xx-xx-001
Installation above the lower diaphragm seal
P01-FMD7xxxx-05-xx-xx-en-002
Diagram of maximum installation height above the lower diaphragm
seal for vacuum applications dependent on the pressure at the
diaphragm seal on the positive side
Heat insulation – FMD77
The FMD77 must only be insulated up to a certain height. The maximum permitted insulation height is
indicated on the devices and applies to an insulation material with a heat conductivity 0.04 W/(m x K) and
to the maximum permitted ambient and process temperature ( see table below). The data were determined
under the most critical application "quiescent air".
T A
λ ≤ 0.04
W
mK •
T P
Maximum permitted insulation height
P01-FMD77xxxx-11-xx-xx-xx-000
Endress+Hauser 67
AoteWell International.inc sales@aotewell.com Tel: +852-6563-2160