Australian Pipeline Valve - Installation, Operation and Maintenance Manual
12
SIDE ENTRY 2P TRUNNION BALL VALVES API6D STANDARD - FS9000 SERIES
torque required to unseat it will increase. Teflon is not suitable for larger sizes and higher pressures.
Regardless of soft seat material, valves need to be regularly partially stroked to prevent sticking of seats
and accumulation of entrapped debris. However, all soft seated valves are only suited to clean service
applications.
3 . 0 R E M O V A L F R O M L I N E
It is desirable that the maintenance operations are carried out by skilled personnel who are experienced
and well trained in standard field techniques and procedures. Be sure that the personnel involved in such
operations are aware of fundamental safety rules indispensable for the protection of their own and other
people’s safety. Ball valves are field maintainable, hence to carry out normal maintenance (stem
lubrication, stem packing substitution, seat lubrication) it is not necessary to remove it from line (seat
lubrication is only for emergency purposes not for maintenance).
If it is required to remove the valve from the line proceed as follows:
a- Ensure the line is fully depressurised.
b- Partially open the ball in order to depressurise the valve.
c- Remove the drain plug and vent plug. First release vent to ensure no remaining pressurised gas or fluid
trapped in cavity. Take safety precautions to avoid personal injury during this procedure. Then carefully
remove drain plug once you are sure valve has no remaining fluid or gas in cavity.
d- Keep the ball in the fully open position.
e- Remove the valve from the line. The valve shall be handled by means of lifting lugs fitting on the valve
(if applicable). Standard field techniques and procedures are satisfactory to disconnect it from the line.
f- After removal of the valve from the line, clean the valve and seal the ends with plastic or wooden
covers.
Stem seal body leakage can result in personal injury. If the valve has an adjustable
gland packing, then tighten it if a leak occurs in the stem area. Some sizes & classes
have a triple barrier internal stem seal and cannot be ‘adjusted’ like a gland
packed ball valve. In an emergency if tightening gland packing nuts (where fitted)
fails, injecting grease into the grease sealant injection nipple fitted to stem (where
fitted) may temporarily cause the leakage to cease (refer 8.2) but the valve should
be removed from the line for repair as soon as possible.
4 . 0 G E A R B O X R E M O V A L
a- Removal (refer to enclosed drawings)
• Unscrew the bolts/nuts.
• Lift the gear box to disengage the valve stem and remove it with the plate.
b- Put in position a removable cover to prevent the introduction of dust, sand, etc in the actuator bushing.
