Deltabar S
Hauser
59
Observe the installation instructions regarding capillary tubes. See
Filling oil
When selecting the filling oil, fluid and ambient temperature as well as the operating pressure are of crucial
importance. Observe the temperatures and pressures during commissioning and cleaning. A further selection
criterion is the compatibility of the filling oil with the requirements of the process medium. For this reason,
only filling oils that are harmless to health are used in the food industry, such as vegetable oil or silicone oil.
See also the following section "Diaphragm seal filling oils".
The filling oil used influences the T
K
zero point and the temperature operating range of a diaphragm seal system
and the response time.
60 ff, sections "Influence of the temperature on the zero point" and "Response
Differential pressure transmitter
The differential pressure transmitter influences the temperature operating range, the T
K
zero point and the
response time as a result of the volume of its side flange and as a result of its volume change. The volume
change is the volume that has to be shifted to pass through the complete measuring range.
Differential pressure transmitters from Hauser are optimised with regard to minimum volume change
and side flange.
Diaphragm seal filling oils
Version
1
Filling oil
Permissible
temperature range at
0.05 bar
p
abs
1 bar
Permissible
temperature range
at p
abs
1 bar
Density
Viscosity
Coefficient
of thermal
expansion
T
K
correction
factor
Notes
[g/cm
3
] [cSt at
25°C
(77°F)]
[1/K]
FMD77: A
FMD78: A, 1
Silicone oil
–40...+180°C
(–40...+356°F)
–40...+250°C
(–40...+482°F)
0.96
100
0.00096
1
suitable for foods
FDA 21 CFR 175.105
FMD77: V
FMD78: C, 3
High-
temperature oil
–10...+200°C
(+14...+392°F)
–10...+400°C
(+14...+752°F)
1.07
37
0.0007
0.72
high temperatures
FMD77: F
FMD78: D, 4
Inert oil
–40...+80°C
(–40...+176°F)
–40...+175°C
(–40...+347°F)
1.87
27
0.000876
0.91
Oil for ultra pure gas
and oxygen
applications
FMD77: D
FMD78: B, 2
Vegetable oil
–10...+120°C
(+14...+248°F)
–10...+200°C
(+14...+392°F)
0.94
9.5
0.00101
1.05
suitable for foods
FDA 21 CFR 172.856
FMD77: L
FMD78: E, 5
Low
temperature oil
–70...+80°C
2
(–94...176°F)
–70...+180°C
2
(–94...+356°F)
0.92
4.4
0.00108
1.12
low temperatures
1)
Version for feature 90 in the order code
2)
Observe temperature limits of the device (
