Australian Pipeline Valve - Installation, Operation and Maintenance Manual
17
LUBRICATED PLUG VALVES - SAPM/SAPL
smaller size and lower pressure plug valves, ‘packing sticks’ are used and can be screwed in through the
top of the stem with a bolt in lieu of using a grease fitting. If there is no body grease fitting, then the
sealant channel on top of the stem supplies sealant to the plug and the seat. Bolted style gland packed
valves do usually (optionally in smaller sizes) have a separate stem sealant injector but this is only needed
in an emergency to temporarily seal a damaged stem seal (refer to Appendix B and C).
The purpose of lubrication is for 3 reasons:-
- To protect the surface seal of the valve from corrosion and abrasion.
- To contribute to a good seal.
- To contribute to an easy action.
The frequency of re-lubrication depends upon the operating conditions from the required mode of
sealing. Generally the valve should be regreased every 3 or 4 operations of the valve especially if used
high pressure gas however it depends entirely on the period between each operation of the valve.
The following tables gives you the minimum frequency of re-lubrication according to the temperature
range and service type. ANSI class 600 and above should be greased more frequency especially if the
media is high pressure gas. Special grease should be used for low and high temperature.
The quantity of grease for re-lubrication also depends on the operating conditions, however the usual
amount is about 2 gr/mm of passage.
TABLE 1
Frequency of lubrication using temperature as a guide
TEMPERATURE RANGE TEMPERATURE RANGE
-28º to -1ºC
6 months
0º to 100ºC
12 months
-50º to 29ºC
6 months
100º to 150ºC
3 months
150º to 180ºC
2 months
over 180ºC
1 month
TABLE 2
Frequency of lubrication using service as a guide
SPECIAL CONDITIONS
FREQUENCY OF SEALANT INJECTIONS
Infrequent operation, valve either fully opened or fully
closed. Non abrasive gases or liquids.
Every 20 operations, minimum once per year. But,
depends on media, temperature, etc.
Infrequent operation, valve either fully opened or fully
closed. Abrasive gases or liquids.
Every 10 operations, minimum 5 times a year. But,
depends on media, temperature, etc.
Throttling services and abrasive slurries.
Every 5 operations, minimum 12 times a year. But,
depends on media, temperature, etc.
