Preparing The Valve For Service Work; Installing The Valve After Service Work - Samson 3291 Translation Of Original Instructions

9.2 Preparing the valve for
service work
WARNING
!
Risk of personal injury due to incorrect
removal of the anti-rotation fixture under
tension.
Once the actuator has been mounted on the
valve and the assembly is ready for use, the
clamps (301) of the anti-rotation fixture on
the plug stem are under tension.
Î Follow the instructions in this document
during mounting or removal.
Î Do not loosen the screws (303) of the an-
ti-rotation fixture while the force generat-
ed by the supply air and/or the actuator
springs is transmitted to the actuator stem
and the stem (9).
Î First remove the actuator from the valve
or ensure it cannot transmit any forces to
the actuator stem before removing the
anti-rotation fixture on the plug stem.
1. Lay out the necessary material and tools
to have them ready for the service work.
2. Put the control valve out of operation (see
the 'Decommissioning' section).
3. Remove the actuator from the valve. See
associated actuator documentation.
Note
To remove an actuator with "stem extends"
fail-safe action and/or with preloaded
springs, a certain signal pressure must be
applied to the actuator (see associated actu-
ator documentation). Afterwards, the signal
EB 8072 EN
pressure must be removed and the air supply
disconnected again and locked.
Tip
We recommend removing the valve from the
pipeline before performing any service work
(see the 'Removal' section).
The following service work can be per-
formed after preparation is completed:
− Replace the gaskets (see section 9.4.2)
− Replace the packing (see section 9.4.3)
− Replace the seat and plug (see sec-
tion 9.4.4)
9.3 Installing the valve after
service work
1. Mount actuator. See associated actuator
documentation and the 'Installation' sec-
tion.
2. Adjust lower or upper signal bench
range. See associated actuator docu-
mentation.
3. If the valve has been removed, re-install
the valve into the pipeline (see the 'Instal-
lation' section).
4. Put the control valve back into operation
(see the 'Start-up' section). Observe the
requirements and conditions for start-up
or putting the valve back into operation.
Servicing
9-5