Flowserve NAF-Setball ball sector valve - Manual (Page 4)

4
8 Spare Parts
When placing orders for spare parts, specify:
1. Product code of the valve - incl. DN according to
Fk 41.51 and Fk 41.54 and the Manuf. No.
specified on the identification plate of the valve.
2. Description of the part, its item No and quantity
required. See table section 7.
Ordering example: NAF 8780EB-0100-02,
manuf. No. 1234567,
Seatring item 11
Quantity 1 pc.
9. Maintenance
Many valves are installed in such locations that their
performance is of vital importance to the entire process.
Such valves should be inspected regularly and any faults
should immediately be corrected.
Exhaust fuse
The primary exhaust fuse consisting of bearing seat (9)
and locking segment (8) and the secondary exhaust fuse
consisting of washer (26) and bolt (28) should always be
inspected during maintenance. See section 9.7.
In older valves, before 1992, a keyway ring (35) can be
mounted as the secondary exhaust fuse instead of the
washer (26) and bolt (28). The design with keyway ring is
no longer a part of our product range. If it needs to be
changed a new stem must be mounted.
To ensure the safety of the valve the primary and secon-
dary exhaust fuse must be correctly mounted.
Stem sealing
The stem sealing should be changed regularly and in
intervals that are in proportion with the use of the valve.
9.1 To remove the valve from the pipework
Ensure that the valve is free of pressure.
The procedure is as follows:
1. Ensure that the recommended spare parts and
the gaskets for the pipe flanges are available.
2. Close the valve.
3. Shut off all compressed air connections
and isolate all electrical connections to the
actuator.
4. Disconnect all compressed air lines and electric
cables connected to the actuator.
5. Release the flanged joint between the valve
and the pipework. Then lift out the valve. Don’t
use the actuator for lifting. Apply all lifting
forces to the valve itself and not to the actuator
- see fig. 1.
Note the flow direction which is shown by an
arrow on the valve body.
9.2 To change the stem seal of O-ring type.
The upper o-ring (13) should be changed if the upper
stem sealing is leaking.
Ensure that the valve is free of pressure.
1. Dismount the actuator.
2. Remove the key.
3. Loosen the bolts (21) and remove the gland
cover (5).
Then remove the o-rings (13) and (15) as well as
the washer in PTFE (14).
Inspect the primary and secondary exhaust
fuse, see section 9.7.
4. Clean and inspect all easily accessible surfaces.
The surfaces must be completely free from
scratches. Remove any burrs from the keyways.
5. Replace the two o-rings (13) and (15) as well as
the washer in PTFE (14). Grease the o-rings with
suitable silicone grease.
6. Mount the gland cover (5) with the bolts (21).
9.3 To change and inspect the upper stem seal,
boxpacking
The sealing requires inspection and adjustment when it
has been taken into operation.
Ensure that the valve is not under pressure.
1. Dismount the actuator.
2. Remove the nuts (18). Lift off the gland
cover (16). Then remove the boxpacking (19C).
Inspect the primary and secondary exhaust
fuse, see section 9.7.
3. Clean the surfaces of the stem, gland cover (16)
and the recess in the valve body.
4. Carefully examine the stem surface to make sure
that it is completely free from marks and
scratches.
5. Replace the boxpacking (19C) with a new one.
Then mount the gland cover (16) and the
nuts (18).
6. Tighten the nuts (18) until the boxpacking gets in
place and is in contact with both the stem and
valve body. Check the tightness of the packing
and retighten the nuts (18) – if necessary - when
the valve is taken into operation.