Samson 3525, Монтаж и эксплуатация

Страница: 14 / 56

14 EB 8823 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
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
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.
1 Body
2 Bonnet
3 Yoke
4 Seat
5 Plug (29, 36)
7 Guide bushing
11 Spring
12 Washer
15 Packing (11, 12, 16)
16 V-ring packing
17 O-ring
29 Plug head
36 Plug stem
92 Lock nut
112 Screw plug
127 Seat ring gasket
A7 Actuator stem
A16 Vent plug
A28
Stem connector clamp
S Signal pressure connection
3
92
112
29
4
17
16
A7
A28
S
A16
1
2
36 5
7
12
11
15
127
Fig. 5: Compact version Type 3525
T-pattern Valve with Type 3571
Pneumatic Actuator