Australian Pipeline Valve - Installation, Operation and Maintenance Manual
10
SIDE ENTRY 2P TRUNNION BALL VALVES API6D STANDARD - FS9000 SERIES
Note
Do not operate the valve during flushing or entrained particulates could damage
soft seat or enter stem or seat pocket area.
2.5 MAINTENANCE POST FLUSHING
a- At the end of flushing operation it may be possible to leave the line full of test fluid and in this case no
intervention is required. If the line must be drained proceed as follows:
• Make sure that the valve is in full open position.
• Open plugs and drain it completely. Observe safety plant procedures prior to opening any body plugs in
case any remaining fluid or gas is pressurised or trapped in body cavities.
• After draining flush the cavity of valve through the vent plug. Consult an expert on use of special
excavation procedures.
• Lubricate the stem with fluid protective oil or grease through the injector (if applicable). (Seat
lubrication is normally only required for emergency purposes not for ongoing maintenance).
• Completely tighten all drain and vent plugs. Consult your plant safety procedures and only perform
work under supervision of expert valve maintenance personnel.
b- Operate the valve at least 2 times (complete closing and opening operation).
c- Repeat the operation every 6 months if the pipeline is not used.
d- Always get authorisation to partially operate an in-service valve.
Personal injury may result from sudden release of any process pressure. APV
recommends the use of protective clothing, gloves and eye wear when performing
any installation or maintenance. Never unscrew sealant injection nipples from body,
seats or stem, as these outlets are exposed to full line pressure and only the in-built
check valve in the sealant nipple itself isolates the pressure. Similarly the body
drain and vent valve plugs are exposed to full line pressure if opened.
Natural gas is not usually clean. Natural gas may carry condensates and dirt that
gets trapped in the valves, and may damage the internal parts. Also, operation of
the valves becomes more difficult. It is true that plant sites do install filters in their
system, but experience has proven that no system is perfect. The internal parts of
the valve can be partially protected using judicious amounts of grease to fill the
cavities. However, other than when flushing (see 2.4.3) or if there is seat leakage,
or if valve cannot be opened, no grease should be applied via seat sealant injectors
to soft seats as it will attract debris and cause damage. A soft seated valve is
always at risk if service is not clean.
