28
EB 8310-8 EN
Decommissioning and disassembly
9 Decommissioning and disas-
sembly
Risk of bursting in the actuator.
Actuators are pressurized. Improper opening
can lead to actuator components bursting.
Before starting any work on the actuator, de‑
pressurize all plant sections concerned and
the actuator.
Risk of personal injury due to preloaded
springs.
Actuators with preloaded springs are under
tension. They can be identified by the long
bolts protruding from the top and bottom di‑
aphragm cases.
Before starting any work on the actuator, re‑
lieve the compression from the preloaded
springs (see section 9.3).
9.1 Decommissioning
To decommission the actuator for service and
repair work or disassembly, proceed as fol
-
lows:
1. Put the control valve out of operation.
See associated valve documentation.
2. Disconnect the pneumatic air supply to
depressurize the actuator.
9.2 Removing the actuator
from the valve
1. Put the control valve out of operation.
See associated valve documentation.
2. Remove the stem connector clamps
(A26/27).
3. Unscrew the stem connector nut and lock
nut from the valve.
4.
Removing actuators with "stem ex-
tends" action with/without preloaded
springs:
to undo the ring nut (A8), apply
approx. 50 % signal pressure to open the
valve.
5. Unscrew the ring nut on the valve bon
-
net.
6. Disconnect the signal pressure again.
7. Separate the actuator from the valve by
undoing the ring nut.
8. Fasten the lock nut and stem connector
nut on the valve.
9.3 Relieving the spring com-
pression in the actuator
1. Unthread the short nuts (A21) and bolts
(A20) on the diaphragm cases.
2. Unscrew the the long nuts (A23) and
bolts (A22) on the diaphragm cases
evenly in a crisscross pattern.
9.4 Disposal
Î
Observe local, national, and internation
-
al refuse regulations.
DANGER
!
WARNING
!