Samson 3349 Mounting And Operating Instructions page 68

Decommissioning
Î Before unblocking the actuator and plug
stem after they have become blocked
(e.g. due to seizing up after remaining in
the same position for a long time), re-
lease any stored energy in the actuator
(e.g. spring compression). See associat-
ed actuator documentation.
WARNING WARNING
! !
Risk of personal injury due to exhaust air
being vented.
While the valve is operating, air is vented
from the actuator, for example, during
closed-loop operation or when the valve
opens or closes.
Î Wear eye protection when working in
close proximity to the control valve.
WARNING WARNING
! !
Risk of personal injury due to residual
process medium in the valve.
While working on the valve, residual me-
dium can flow out of the valve and, depend-
ing on its properties, cause personal injury,
e.g. (chemical) burns.
Î Wear protective clothing, safety gloves,
respiratory protection and eye protec-
tion.
10-2
NOTICE
!
Diaphragm damage through the use of an
incompressible medium.
Closing the valve when the shut-off valves
upstream and downstream of the valve are
closed may lead to the diaphragm rupturing
in plants with liquid media flowing through
them.
Î Only close the valve when the shut-off
valves upstream and downstream of the
valve are open.
To decommission the control valve for service
work or to remove it from the pipeline, pro-
ceed as follows:
1. Close the shut-off valves upstream and
downstream of the control valve to stop
the process medium from flowing
through the valve.
2. Completely drain the pipelines and
valve. Use the valve connection at the
side to drain the valve.
3. Disconnect and lock the pneumatic air
supply to depressurize the actuator.
4. Release any stored energy.
5. If necessary, allow the pipeline and valve
components to cool down or warm up to
the ambient temperature.
EB 8048-2 EN