TOV
Installation, Operation and Maintenance Manual
15
WKM-TOV-IOM
Sealing elements maintenance
Packing maintenance
Fig: 4.1
using Molykote ® Spray
– 321 R (Dry lubricant) or
equivalent and also to the external edge (sealing
conical surface) of the seal rings.
15. The disc (6) shall be rotated 90° clockwise (fully open
position from 180°).
16. The gear box (31) shall be assembled.
17. The valve shall be seated and unseated twice by using
the gear box.
18. The valve shall be kept in the closed position without
applying torque to avoid the seal ring moving from the
position.
19. With the valve in the closed position, all the retaining
ring screws (29) shall be tightened using star pattern
as per Figure 9.
a. Packing nuts are tightened as per the torque
chart.
Caution:
Bolt torque shall be applied in small increments (25 percent
of final torque) so that gasket is compressed evenly.
Caution:
Seal and seat shall contact uniformly
around circumference. No light shall be visible around seal.
1. The valve shall be removed from the line with the disc (6)
in the closed position.
2. The valve shall be fully open (90°) by using the gear box
(31).
3. The gear box (31) shall be removed from the valve.
4. The valve shall be opened further 90° counterclockwise
(up to 180° from the closed position along with shaft
[Figure 8]).
a. If needed, the packing nuts shall be loosened for
frictionless rotation.
5. The seal retainer screws (29) shall be removed and the
seal retainer shall be carefully removed (28).
6. The seal ring assembly (27) and the graphite gasket (26)
shall be removed.
7. The body seat shall be inspected and cleaned with a fine
abrasive cloth (No. 600 or finer), if necessary.
8. The disc seal ring area and serrations shall be inspected
and cleaned. No foreign particles shall be present on the
serrations where GHR gasket (26) will be placed.
9.
A thin film of light mineral oil shall be applied on the
surface area of the disc where seal ring (27) will be
located.
Caution:
Serration surfaces shall be fully cleaned such that no
foreign particles are present.
10. The new GHR gasket (26) shall be assembled on the
serration surface.
11. Seal ring (27) shall be replaced after making sure that the
slot on the edge of the seal ring (27) is in correspondence
with the locating pin (25).
12. The seal retainer ring (28) shall be assembled after making
sure that the slot on the edge of the seal ring (27) is in
correspondence with the locating pin (25).
13. All the fastening screws (29) shall be hand tightened after
applying Loctite ® type 242 or equivalent on the threads.
Then, verify that the seal ring can be moved freely by hand
without rotating it.
14. A thin film of lubricant shall be applied to the body seat
Figure 8:
Sealing elements
maintenance
