5 FT 70 en
9
4.6
Changing the seat
4.6.1
FC series
The seat can be replaced without dismantling the valve.
A ’spring-to-close’ actuator need not be detached in order
to change the seat. Double-acting (e.g. B1C) and ’spring-to-
open’ actuators should be detached.
4.6.1.1 With the actuator installed
Remove the valve from the pipeline as described
above.
Before starting to dismantle the valve operate first
valve to fully closed position. If the actuator installa-
tion is ’spring-to-open’, operate the valve to fully
closed position using air pressure specified in Table
5, 6 and 8.
Remove the locking shoulders of the insert (2) and
unscrew the insert using a special tool, see exploded
view and parts list in Section 10. The special tool is
available from the valve manufacturer.
Remove the back seal (63) and unscrew the seat (7)
from the valve body.
Replace the insert (2), seat (7) and back seal (63) with
new parts.
Lubricate the seat (7) threads with Molykote D 321R
or a similar substance. Screw the seat into place by
hand and centre the plug (3) in the closed position
with respect to the seat.
Install the back seal (63) into the insert (2).
Screw the insert (2) onto the threads of the seat (7).
Tighten the insert with a special wrench. The torques
are given in Table 4.
Operate the valve first to fully open position and
loosen the stop screw for closed position, see Fig. 20
for QP actuators, Fig. 22 for series B and Fig. 27 for E
series actuators.
Now operate the valve to fully closed position using
air pressure specified in Table 5, 6 and 8.
Screw in the stop screw to light contact with the pis-
ton inside the actuator and lock the screw with a
locking nut.
Keep your fingers out of the flow bore!
Lock the insert by hitting it with a nail punch to
make juts over two of the four available notches on
the body.
4.6.1.2 With the actuator detached
Remove the valve from the pipeline and the actuator
from the valve as described above.
Before starting to dismantle the valve operate the
valve to fully closed position with proper handlever
using torque value specified in Table 11.
Remove the locking shoulders of the insert (2) and
unscrew the insert using a special tool, see exploded
view and parts list in Section 10. The special tool is
available from the valve manufacturer.
Remove the back seal (63) and unscrew the seat (7)
from the valve body.
Replace the insert (2), seat (7) and back seal (63) with
new parts.
Centre the plug (3) in the closed position relative to
the flow port by turning the stem (5) with a hand
lever.
Lubricate the seat threads with Molykote D 321R or a
similar substance. Screw the seat (7) into place by
hand and centre the plug in the closed position with
respect to the seat, by turning the stem with the
hand lever using torque specified on Table 11.
Install the back seal (63) into the insert.
Screw the insert (2) onto the threads of the seat (7).
Keep the seat (7) in place with the help of the plug
(3) by turning the stem with the hand lever using
torque specified on Table 11. At the same time
tighten the insert (2) with a spanner wrench using
torque specified on Table 4.
Lock the insert by hitting it with a nail punch to
make juts over two of the four available notches on
the body.
Install the actuator and adjust the limits (see Section 6).
4.6.2
FL series
Turn the valve into closed position and place it verti-
cally the seat side pipe flange toward a planar sur-
face. Make sure that the surface is soft enough to
prevent the pipe flange surface damages.
There are two alternatives to remove the pins:
a) carefully drill a 2 mm hole that is 10…12 mm deep
to both pins (14) and remove the pins (14), shaft (12)
and drive shaft (11),
b) in the new versions where the pin drilling is made
through the ball remove the pin locking made with
centre punch carefully by drilling, turn the ball 180
degrees and push the pins via the hole. See Fig. 16.
Remove the key (13) from the shaft (11). Unfasten
the blind flange bolts (26) and remove the blind
flange (10) and seal (19). Unfasten the nuts (25) and
remove the disc spring sets (32), retainer plates (30)
and gland (9). Remove the bearings (16, 17).
CAUTION:
Beware of the plug cutting movement!
NOTE:
The seat cannot be replaced without dismantling the
valve.
Fig. 16
Drilling the pin
Cylindrical pin
part no. 14
