Emerson VANESSA 30,000 Series Installation, Operation And Maintenance Manual page 7

VANESSA SERIES 30,000 TRIPLE OFFSET VALVE (TOV)
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
4.2 Sealing elements maintenance
To replace the sealing elements proceed as
follows (refer to figure 5):
WARNING
Depressurize the line before starting any
maintenance. Failure to do so may cause serious
personnel injury and/or damage to the valve.
1. Remove the valve with the disc in the closed
position from line. Clean the valve according
to proper cleaning procedure as outlined
by the plant or according to a recommended
procedure.
2. Open the valve a few degrees.
3. Loosen the seal retainer flange screws (2c).
If screws are secured, unbend the bevel.
4. Open valve to full open position.
NOTICE
In small size valves it may be easier to remove
the actuator and rotate the disc beyond the
full-open position to provide more space to work
with components.
5. Carefully remove the seal retainer flange
screws (2c) with security washers (2d) if
present, then remove the seal retainer
flange (2b).
6. Remove seal ring (3a) and spiral wound
gasket (3b).
7. Inspect the body seat. Clean it, if necessary,
with fine abrasive cloth (No. 600 or finer),
after having cleaned it perfectly with solvent.
8. Inspect and clean the disc seal ring area
and spiral wound gasket groove. No foreign
particles must be present before spiral
wound gasket and seal ring assembly.
FIGURE 5
9. Apply a thin film of lubricant on the surface
area of the disc (2a) where seal ring (3a)
and spiral wound gasket (3b) will be located
(lubricant should be in accordance with
Table 3).
CAUTION
Apply only a thin film of lubricant where indicated.
Failure to do so will hinder the assembly and may
cause damage to the valve.
10. Assemble the new spiral wound gasket
(3b) in the disc groove, without forcing and
taking care not to damage it.
11. Replace seal ring (3a) on the disc through
the shaft side of the body. To properly
locate the seal ring refer to figure 6: align
the internal slot of the seal ring (3a) to the
reference pin (F).
12. Assemble the seal retainer flange (2b).
Refer to figure 6: make sure that the slot on
the edge of the seal retainer flange (B) is in
correspondence with reference pin (F).
13. Hand tighten all the fastening screws (2c),
with relevant lock washers (2d) if present,
after applying Loctite 270 or equivalent on
®
the bottom side of the threads (ensure they
are perfectly clean with a solvent before
applying Loctite ). Then, verify that the seal
®
ring can be moved freely by hand without
rotating it.
14. Apply a thin film of lubricant to the body seat
and to the external edge (sealing conical
surface) of the seal ring (3a). Lubricant
should be in accordance with Table 3.
15. Seat and unseat the valve twice.
16. Keep the valve in the closed position without
applying torque. Tighten at least two
retaining screws (2c) to avoid the seal ring
moving from the position found.
17. Open the disc a few degrees and tighten, using
a torque wrench, all screws (2c). Use a torque
value from Table 2 (refer to figure 6).
It is recommended to use a cross-pattern
tightening sequence to tighten all retaining
screws.
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