Australian Pipeline Valve - Installation, Operation and Maintenance Manual
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IRON GATE & GLOBE VALVES - SL201, SL600, SL601
9 . 0 PREVENTATIVE MAINTENANCE
1. Inspect whether all valves can be opened or closed smoothly at least once a month. If the operation is
sluggish, clean the spindle threads and lubricate the same.
2. Check the gland tightening nuts for any slackness, if required tighten these nuts and ensure that the
valve operation is not hampered by over tightening the gland.
Note, use suitable new gland packing rope/rings of correct size and type when replacing.
1 0 . 0 STEM PACKING/ BACK SEATING
Use Graphite (Graphoil)/PTFE impregnated Graphoil/Pure PTFE packings as per permissible limits of line
pressure, temperature as well as media of flow through the valves. Some styles only have an O-ring stem
seal system so ensure the grade of O-rings suits the service media and temperature.
If back seating feature is provided, for normal operation in the open position, the stem should be backed
off so that the backseat is not in contact. This permits the stem packing to assume it’s intended sealing
function and not conceal unsatisfactory stem packing. In the event of stem packing leakage, the back seat
can be used to stop stem leakage until circumstances permit a system shutdown and time for packing
replacement. Stem packing replacement with the valve under pressure and backseated represents a
hazard and should not be undertaken. The hazard is magnified as fluid pressure or temperature increases
or when the fluid is toxic.
1 1 . 0 L E A K A G E A C R O S S G A S K E T
Should any bonnet gasket leaks occur, tighten the bolts/nuts & studs (refer Diagram 2, Appendix A). If
leakage still persists, the bonnet gasket should be changed.
1 2 . 0 M A J O R M A I N T E N A N C E
Only an expert valve re-conditioner should attempt the following major extraordinary maintenance/
repairs.
Do not attempt to repack the stem packing in line while the valve is under pressure.
The line must be totally purged. Cast iron valves do not all have the ‘back seating’
feature. Prior to removing bonnet, exercise extreme caution no pressure is trapped
in the valve cavity. Wear appropriate safety apparel and follow industry and plant
safety procedures.
