Planning Instructions For Isolating Systems; Influence Of The Components - Vega VEGADIF 65 Operating Instructions Manual

3 Planning instructions for isolating systems

Separating diaphragm
Capillaries
Chemical seal filling oil
Filling oil
Silicone oil KN17
Silicone oil KN2.2
High temperature oil
KN32
High temperature oil
KN32
Halocarbon oil KN21 -40 ... +150 °C (-
6
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:
•
Diameter
•
Resilience
•
Material
The bigger the diaphragm diameter, the higher the resilience and the
smaller the temperature influence on the measuring result. Note: To
keep this influence within reasonable limits, you should use a chemi-
cal seal with a nominal width ≥ DN 80.
The resilience also depends on the diaphragm thickness, the material
as well as a possible coating.
The capillary line influences the temperature coefficient TK
the permissible ambient temperature and the step response time of
an isolating system through its length and inner diameter. See also
chapter "Influence of the temperature on the zero point", "Ambient
temperature range" and "Step response time".
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 with the require-
ments of the medium. In the food processing industry, for example,
only filling oils that present no health risks are permitted, e.g. medici-
nal white oil. See overview of filling oils in the following chart.
The table also shows the permissible medium temperature depending
on the isolating liquid and instrument version for p
For the medium temperature with instrument version for p
< 1 bar/14.5 psi, see chapter "Chemical seal for vacuum applica-
tions".
Permissible medium
temperature with p
abs
> 1 bar/14.5 psi
-40 ... +180 °C (-
40 ... +356 °F)
-40 ... +200 °C (-
40 ... +392 °F)
-10 ... +300 °C (-
14 ... +572 °F)
-10 ... +400 °C
(+14 ... +752 °F)
40 ... +302 °F)
Density in Kinemat-
g/cm³ at ic viscosity
25 °C in cSt at
25 °C
0.96 4.4
0.96 54.5
1.06 47.1
1.06 47.1
1.89 10.6
> 1 bar/14.5 psi.
abs
Corrective Application area
factor for
TK
1 Low temperatures
1 Standard
0.77 High temperatures
0.77 High temperatures
0.83 For chlorine appli-
cations
Chemical seal CSB • for VEGADIF 65
,
Zero point
abs