ARI Armaturen STEVI AS 350 DN15-50 EN - Manual (Page 4)

Page 2-4 Rev. 0040322000 3413
Operating and installation instructions
Y-pattern processing valve - STEVI
®
AS 350
Depending on application different types are possible:
1. Spring closes on air failure (NC)
Fig. 1:
When applying pressure, the air supply
pressure moves the piston against the
spring, lifts the plug from the seat and the
valve opens.
2. Spring opens on air failure (NO)
Fig. 2:
In the rest position, the valve is held by a
spring below the piston in the open position.
The valve closes by introducing the air
supply pressure.
3. Double acting (DA)
Fig. 3:
There is no sping installed in the actuator.
The valve opens and closes only by air supply pressure
Connection 1
Spring closes /
Air supply pressure
opens
Connection 2
Spring opens /
Air supply pressure
closes
Connection 1
Air supply pressure opens
Connection 2
Air supply pressure closes