Samson 3767 Mounting And Operating Instructions page 35

Actuator stem retracts (FE):
Fail-open
(for globe and angle valves)
For tight-closing valves, the maximum signal
pressure pstmax is roughly estimated as fol-
lows:
d² · π · ∆p
pst = F +
max
4 · A
d = Seat diameter [cm]
∆p = Differential pressure across the
valve [bar]
A = Actuator area [cm²]
F = Upper bench range value of the
actuator [bar]
If there are no specifications, calculate as
follows:
Required supply pressure =
Upper bench range value + 1 bar
Pressure regulator
After tilting the cover plate back, the pres-
sure regulator (9) can be continuously ad-
justed. When the adjuster is turned counter-
clockwise as far as it will go, signal pres-
sures for spring ranges up to 2.5 bar are
controlled. When the adjuster is turned
clockwise all the way, signal pressures for
spring ranges up to 6.0 bar are controlled.
If the signal pressure must not exceed a cer-
tain value, this limit can be adjusted using a
pressure gauge (accessories).
EB 8355-2 EN
[bar]
Connections
35