Marwin Valve KC Series Trunnion Valves - Manual (Page 3)

Draining: Perform as mentioned in DBB operation.
Flushing of the valve body is merely a combination
of the DBB and Drain procedure. The vent fitting
can then be removed to allow introduction of flush-
ing media.
Maintenance for ball valve:
Marwin ball valves should provide years of trouble-
free service without routine maintenance. In the
event of leakage the following procedure may be
used to insure continued operation of the valves.
In-Line/Site Maintenance:
The Marwin ball valve has three stem seals: Two o-
ring seals and one fire safe gasket.
Replacement procedure:
1. Perform the DBB action mentioned above and
remove the actuator from the stem, taking care
not to damage the stem and key.
2. Remove the key and put it in a secure place.
3. Insure pressure is not trapped between the two
o-ring seals. Vent the area by depressing the
1/16" rod ball check which is integrated on the
stem sealant injector.
4. Use the appropriate socket to remove the
bolting of the top flange and the gland ring.
Remove the pin which fixes the top flange and
remove the top-flange.
5. Take out the gland ring and stem seal. Install
the new o-ring/gasket and lubricate them for
reinstallation.
6. Install the components in the reverse order of
above steps.
Ball valve major maintenance:
Major replacement of internal components requires
removal of the valve from the pipeline. (The top
entry ball valve are made for inline maintenance.
See top entry procedure for details. For fully
welded ball valve this is not applicable. Replace
with a new valve if needed
).
Equipment required:
Lifting equipment which is suitable for the weight of
handling the valve and its components.
No special tools are required for Marwin Side Entry
Ball Valves. For Marwin Top Entry ball valve special
handling tools are necessary.
Disassembly:
Turn the valve to half-open position and open the
body vent to insure there is not any remaining
pressure. Remove and turn the valve to the closed
position. Remove the operator. Remove the stem
assembly as mentioned above.
-3-
Turn the valve on end and place it on a flat level
surface. (Note: The valve end must be protected to
avoid any damage. )
Remove the body nuts, and lift the cap from the
body. Turn the cap over and place it on a flat surface.
(Note: The valve end must be protected to avoid
any damage. Do not damage any ball surface ).
Loosen the bolts of thefixed ring allowing removal
of the seat ring from the body/cap socket. Clean
the socket sealing face in the body/cap socket and
slightly lubricate the socket with grease. Replace the
new seat ring valve (includes a whole set of soft seals
and fire safe seals) in the reverse order and tighten
the bolts of the fixed ring.
From the body: Lift the body from the main valve as-
sembly. Lift the ball and bearing block from assembly.
Place the ball and bearing block in a safe place, tak-
ing care not to damage the ball surface.
Replace the remaining seat ring in the same order
mentioned above.
Reassembly of the valve:
Prepare job.
Thoroughly clean all metallic components with a suit-
able solvent. Inspect all components for signs of wear
or damage.
Pay attention to the sealing areas.
Lubricate all moving metal contact surfaces such as
seat pocket and stem housing area.
Lightly lubricate all seals, gaskets and bearing/wash-
ers.
Re-assembly:
Place on end connection (Cap) on a flat surface with
the ball end up (protect the end face).
Place the new seat ring into the cap socket (spring
must be loaded) and tighten the bolt of the fix ring to
secure the seat ring. (Do not use a hammer or other
similar tools to force the seat ring into the socket ).
Install the bearing plate to the ball and lift the ball,
checking if the bearing plate can freely rotate.
Install the body seal over the cap nose. Lower ball/
bearing block assembly onto installed seat, carefully
aligning dowel pins with holes in the cap.
Lower the body over the ball taking care not to dam-
age seal angle on the body or ball surface. Carefully
align the stem hole in the body with the drive slot in
the ball.
Install the stem assembly.
Install the other cap (assembled) aligning carefully
with the bearing block pin and the dowel hole. (The
other set of body seals must be assembled).