VEGA VEGADIF 65 Chemical seal CSS - Manual (Page 5)

3 Planning instructions for isolating systems
3.1 Influence of the components
The following properties of the separating diaphragm determine the
application area of the chemical seal:
l
Diameter
l
Resilience
l
Material
The bigger the diaphragm diameter, the higher the resilience and the
lesser the temperature influence on the measuring result. Note: To
keep this influence in reasonable limits, you should use a chemical
seal with a nominal width ≥ DN 80.
The resilience also depends on the diaphragm strength, the material
as well as a possible coating.
In the selection of filling oil, product and ambient temperature as well
as process pressure are of utmost importance. Also take note of
temperatures and pressures during setup and cleaning.
Another criterium is the compatibility of the filling oil to the require-
ments of the medium. In the food processing industry, e.g., only filling
oils that present no health risks are permitted, such as medicinal white
oil. See overview of filling oils in the following chart.
Filling oil Permissible
product temper-
atures Permissible
product temper-
atures at
0.05 bar
abs
< p
< 1 bar
abs
Densi-
ty in g/
cm³ Vis-
cosity
in m
2
/
s•10 -6
Expan-
sion co-
efficient
1/K
Cor-
rective
factor
for TK Application
area
Silicone oil
KN17 -40 … +180 °C
(-40 … +356 °F) -40 … +80 °C
(-40 … +176 °F) 0.96
up to
25 °C 55
up to
25 °C
0.00104 1 Standard
silicone oil
KN2.2 -40 … +200 °C
(-40 … +392 °F) -40 … +150 °C
(-40 … +302 °F) 0.96
up to
20 °C 55
up to
20 °C
0.00104 1 Standard
High tempera-
ture oil KN 3.1 -10 … +300 °C
(-14 … +572 °F) -10 … +200 °C
(+14 … +392 °F) 1.07
up to
20 °C 39
up to
20 °C
0.0008 0.77 High tem-
peratures
High tempera-
ture oil KN 3.2 -10 … +400 °C
(+14 … +752 °F) -10 … +200 °C
(+14 … +392 °F) 1.07
up to
20 °C 39
up to
20 °C
0.0008 0.77 High tem-
peratures
Halocarbon oil
KN21 (BAM
tested) -40 … +150 °C
(-40 … +302 °F) -40 … +80 °C
(-40 … +176 °F) 1.968
up to
20 °C 14
up to
20 °C
0.00086 0.83 For oxygen
and chlorine
applications
Med. white oil
KN92 (FDA
approved) -10 … +250 °C
(+14 … +482 °F) -10 … +160 °C
(+14 … +320 °F) 0.85
up to
20 °C 5.6
up to
40 °C 0.00065 0.63 suitable for
foodstuffs
Separating diaphragm
Chemical seal filling oil
Chemical seal CSS • for VEGADIF 65 5
3 Planning instructions for isolating systems
36134
-EN
-110926