Georg Fischer DIASTAR SIX Manuel D'utilisation D'origine page 31

Relation between line pressure and spring sets
The closing force of the actuators were designed for the specified PN rating. Operation
with low line pressure can cause increase diaphragm wear. In order to extend the dia-
phragm life span with low line pressure, the number of spring packages can be reduced.
Please contact your +GF+ partner for advice.
Reducing spring sets
Reduced spring sets lead to a reduced closing force. At a rising line pressure
the valve can not close or not close properly due to missing spring sets. Death
Warning
or serious injury could occur due to open piping. The process can be influenced
negatively.
• Configure diaphragm valve and actuator according to your line pressure
Control medium
Information
• 6 bar max. for the FC­mode; lower control pressure possible due to reduced spring sets
• Compressed air class (ISO 8573­1) 2 or 3 for –10 °C and 3 or 4 for T ›0 °C
• Temperature of control medium, max. 40 °C
• When pressure exeeds 10 bar the controll pressure must be throttled by exhaust air
(adjust actuating time to approx. 3 s)
• Please consider control pressure diagrams in the chapter "6.6 Control pressure dia-
grams" or in the Georg Fischer Planning Fundamentals
Control volume
Nominal diameter
20DN15
25DN20
32DN25
40DN32
50DN40
63DN50
Six (FC)
[dm³]
0.07
0.20
0.22
0.40
0.44
0.44
Ten (FC)
[dm³]
0.07
0.20
0.22
0.40
0.77
1.20
Sixteen (FC)
[dm³]
0.20
0.20
0.40
0.78
0.85
1.33
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