VEGA VEGADIF 65 Chemical seal CSB - Manual (Page 8)

8
3 Planning instructions for isolating systems
Chemical seal CSB • for VEGADIF 65
36133-EN-130417
Result: characteristics 2
2. Determine value for TK
Ambient
from the diagram.
Result: 1.4 mbar/10 K
3. T
Ambient
- T
Calibration
= 45 °C - 25 °C = 20 °C; (1.4 mbar/10 K) • 20 K =
2.8 mbar
Result:
In this application case, the zero point is shifted by 2.8 mbar.
The influence of the temperature to the zero point can be corrected by
a position adjustment.
Following the option to the reduce the temperature influence:
•
Smaller capillary inner diameter (note: however, the step response
time increases with reducing diameter)
•
Shorter capillaries
•
Chemical seal with larger diaphragm diameter
•
Filling oil with a smaller expansion coefficient
The following parameters determine the ambient temperature range
of the chemical seal system:
•
Filling oil
•
Capillary length
•
Capillary inner diameter
•
Oil volume of the chemical seal
•
Process temperature
The following diagrams show the permissible ambient temperature
range depending on the capillary length. They apply to a process
temperature of 25 °C and silicone oil. The application range can be
extended by using a filling oil with a smaller expansion coefficient and
shorter capillaries.
•
Group B
– Cell 2" 150-2500 lbs, 316L
– ANSI flange 2" 150 lbs RF, 316/316L
– ANSI flange 2" 300 lbs RF, 316/316L
– Cell DN 50 PN 16-400, 316L
0 1 2 3 4 5 6 7 8 9 10
–40
–20
0
20
40
60
80
Ambient
temperature
[°C
]
Capillary length [m]
Group B
permitted
operating range
Fig. 3: Permissible ambient temperature range depending on the capillary
length for chemical seals of group B
•
Group C
– EN/DIN flange DN 80 PN 10-40 B1, 316L
Reduction of the tem-
perature influence
Ambient temperature
range