Samson 3244 - Actuator Stem Operation and Compatibility

EB 8026 EN 3-3
Design and principle of operation
Actuator stem extends (FA)
When the signal pressure is reduced or the
air supply fails, the springs move the actua-
tor stem downward. In mixing valves, port B
is closed. In diverting valves, port A is
closed.
PortB of diverting valves in sizes DN15 to
25 (NPS½ to 1) is closed as these valves
have the same construction as mixing valves.
Actuator stem retracts (FE)
When the signal pressure is reduced or the
air supply fails, the springs move the actua-
tor stem upward. In mixing valves, port A is
closed. In diverting valves, port B is closed.
PortA of diverting valves in sizes DN15 to
25 (NPS½ to 1) is closed as these valves
have the same construction as mixing valves.
The actuator's direction of action can be re-
versed, if required. Refer to the mounting
and operating instructions of the pneumatic
actuator:
uEB8310-X for Type3271 and Type3277
3.1 Versions
With insulating section/bellows seal
The modular design allows an insulating sec-
tion or bellows seal to be tted to the stan-
dard valve version.
Actuators
In these instructions, the preferable combina-
tion with a SAMSON Type3271 or
Type3277 Pneumatic Actuator is described.
The pneumatic actuator (with or without
handwheel) can be replaced by another
pneumatic actuator in a different size, but
with the same travel.
Î Observe the maximum permissible actu-
ator force.
If the travel range of the actuator is larger
than the travel range of the valve, the spring
assembly in the actuator must be preloaded
so that the travel ranges match. See associ-
ated actuator documentation.
The basic pneumatic actuator can be re-
placed by a pneumatic actuator with addi-
tional handwheel or by an electric actuator
(see Information Sheet uT8300).
3.2 Additional ttings
Strainers
We recommend installing a SAMSON
strainer upstream of the valve. It prevents sol-
id particles in the process medium from
damaging the valve.
Bypass and shut-off valves
We recommend installing a shut-off valve
both upstream of the strainer and down-
stream of the valve and installing a bypass
line. The bypass ensures that the plant does
not need to be shut down for service and re-
pair work on the valve.
Tip
Note