Samson 3222 N - 2 Design and Principle of Operation

2 Design and principle of
operation
The actuator in the three-point stepping ver
-
sion consists of a reversible synchronous
motor and a maintenance-free gear.
The version with digital positioner contains a
stepper motor which can be supplied with
any voltage regardless of the frequency.
Actuator and valve are connected (force-
locking) over a coupling nut (6). An interme
-
diate insulating piece can be used for insu
-
lated pipelines.
The medium flows through the single-seated
globe valve in the direction indicated by the
arrow. The position of the plug (3) deter-
mines the flow rate across the area released
between plug and valve seat (2).
The linear actuating force is transmitted di-
rectly over the actuator stem (7) to the plug
stem (5). When the actuator stem extends,
the valve plug (3) moves in the closing direc-
tion. The plug stem follows the actuator stem
owing to the force of the valve spring (4) as
the actuator stem retracts, causing the valve
to open.
EB 5867 EN 5
Design and principle of operation
Fig. 1 · Type 3222 N/5857 Control Valve
1 Valve body
1.1 Connection nut with gasket and
welding ends (accessories)
2 Seat
3 Plug
4 Valve spring
5 Plug stem
6 Coupling nut
7 Actuator stem
Type 5857
Actuator