Samson 3241, Монтаж и эксплуатация

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16 EB 8012 EN
Design and principle of operation
3.1 Fail-safe positions
The fail-safe position depends on the actua-
tor used.
Depending on how the compression springs
are arranged in the pneumatic actuator, the
valve has two different fail-safe positions:
Actuator stem extends (FA)
When the signal pressure is reduced or the
air supply fails, the springs move the actua-
tor stem downward and close the valve. The
valve opens when the signal pressure is in-
creased enough to overcome the force exert-
ed by the springs.
Actuator stem retracts (FE)
When the signal pressure is reduced or the
air supply fails, the springs move the actua-
tor stem upwards and open the valve. The
valve closes when the signal pressure is in-
creased enough to overcome the force exert-
ed by the springs.
Tip:
The actuator's direction of action can
be reversed, if required. Refer to the
mounting and operating instructions
of the pneumatic actuator:
u
EB 8310‑X for Type 3271 and
Type 3277
3.2 Versions
The modular design allows an insulating sec-
tion or metal bellows to be fitted to the stan-
dard valve version.
Micro-flow valve version
In the micro-flow valve version, a micro-trim
element is installed in the valve body instead
of the usual seat/plug assembly (Fig. 6).
5b
5a
4d
4c
4b
4a
4a Seat body
4b Spring
4c Seat
4d Nut
5a Plug stem
5b Plug
Fig. 6: Micro-trim element