Samson 4765, Монтаж и эксплуатация

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3 Connections
3.1 Pneumatic connections
The pneumatic connections are designed as
tapped holes with ¼ NPT or ISO 2228/1-
G ¼ thread. The conventional male connec-
tions for metal and copper pipes (or plastic
hoses) can be used.
Note:
The supply air must be dry and free of any
oil and dust. Always observe the mainte-
nance instructions applicable to the con-
nected pressure reducing stations. Blow out
air lines thoroughly before connecting them.
3.1.1 Pressure gauges
We recommend attaching pressure gauges
for the supply air and signal pressure in or-
der to monitor the positioner. The parts are
listed as accessories in Table 2 on page 19.
3.1.2 Supply pressure
The required supply pressure is determined
by the bench range and the operating direc-
tion (fail-safe action) of the actuator.
The bench range is written on the nameplate
as spring range or signal pressure range
depending on the type of actuator.
FA
(actu-
ator stem extends) or
FE
(actuator stem re-
tracts) or a symbol indicates the operating
direction.
Actuator stem extends (FA)
Fail-safe position Valve CLOSED
(for globe and angle valves)
Required supply pressure =
Upper bench range value + 0.2 bar,
minimum 1.4 bar.
Actuator stem retracts (FE)
Fail-safe position Valve OPEN
(for globe and angle valves)
The required supply pressure for a
tight-closing valve is roughly estimated from
the maximum signal pressure pst
max
:
pst
max
= F +
d p
A
2
4
× ×
×
p D
[bar]
d = Seat diameter [cm]
D
p = Differential pressure across valve [bar]
A = Actuator diaphragm area [cm²]
F = Upper bench range of actuator [bar]
In the absence of such specifications, pro-
ceed as follows:
Required supply pressure =
Upper bench range value + 1 bar
The signal pressure (output) is routed to the
top or bottom diaphragm case of the actua-
tor as shown in Figs. 6 to 9.
10
EB 8359-1 EN
Connections