8
4.3 Repair of a jammed or stuck
valve while it is in the pipeline
Jamming may be due to the ball (3) and seats (7) becoming clogged
with flow medium. They may be cleaned by turning the ball to the
partly open position and flushing the pipeline. If this does not help,
follow the instructions in the following sections.
4.4 Detaching the actuator
It is generally most convenient to detach the actuator before
removing the valve from the pipeline. If the valve is small or if it is
difficult to access, it may be more practical to remove the entire
package at the same time.
•
Close and detach the actuator pressure supply pipeline and
remove control cables.
•
Unscrew the bracket screws.
•
Detach the actuator. The actuator can be removed by hand or
with a special tool made for this purpose. The tool can be ordered
from the manufacturer (see Section 8 “Tools”).
•
Remove the bracket.
4.5 Removing the valve from the
pipeline
•
Make sure that the valve is not pressurized and that the pipeline
is empty. Make sure that the medium cannot flow into the section
where servicing is to take place.
•
Support the valve carefully with a hoist. Place ropes carefully and
unscrew the pipe flange bolts. See that the ropes are positioned
correctly, see Fig. 7. Lift valve down.
4.6 Dismantling the valve
•
Place the valve in a standing position on the pipe flange end. Use
a level surface that will not scratch the flanges. See that the body
stud nuts (16) are facing upward.
•
Mark the the body halves for correct orientation during re-assem-
bly.
•
Turn the ball to the closed position.
•
Remove the key (10).
•
Unscrew the gland nuts (18). Remove the disc spring sets (150)
and the gland (9).
•
Unscrew the body stud nuts (16).
•
Remove the body cap (2). If the seat (7) is not lying on the ball
(3), prevent the seat from falling from the body cap and detach it
later.
Don’t leave your fingers between the body cap and the
surface!
Stand the removed body cap on its pipe flange.
•
Remove the seat (7) from body cap (2) if it is still in place.
•
Unscrew the bonnet stud nuts (17). Remove the shaft (5) and
bonnet (8). Knock the bonnet off with a piece of wood and a ham-
mer, if needed.
•
Lift the ball (3) along with the trunnion plates (89)out of the body
(1) Handle the ball carefully and place it on a soft surface.
•
Remove the seat (7) from the body (1).
•
Remove the trunnion plates (89) from the hubs of the ball.
•
Remove the trunnion bearings (99) and the bearing spacers (91)
from each trunnion.
•
Push the shaft out of the bonnet.
•
Remove thrust bearings (70, 71) from the shaft and packing rings
(69) from the bonnet (8).
•
Remove the body gasket (65) and the bonnet gasket (66).
4.7 Inspection of removed parts
•
Clean removed parts.
•
See if the shaft (5) or bearings (70, 71, 99) are damaged.
•
See if the ball (3) or seats (7) are damaged (scratched), by exam-
ining them under bright light. The ball and the seat can be
replaced if necessary.
•
See if the body joint sealing surfaces are damaged.
4.8 Replacing parts
We recommend that soft material parts be replaced whenever the
valve is dismantled for servicing. Other parts may be replaced if
necessary. Always use genuine spare parts to ensure proper
functioning of the valve (see section “Ordering spare parts”).
CAUTION
:
When handling the valve or the valve package as a whole, bear in
mind the weight of the valve or the entire package!
CAUTION
:
Do not detach a spring-return actuator unless a stop-screw is
carrying the spring force!
NOTE
:
Before dismantling, carefully observe the position of the valve
with respect to the actuator and positioner/limit switch so as to
make sure that the package can be properly re-assembled.
Fig. 12
Removing the actuator with an extractor
CAUTION:
Do not dismantle the valve or remove pipeline while the
valve is pressurized!
