Australian Pipeline Valve - Installation, Operation and Maintenance Manual
9
IRON GATE & GLOBE VALVES - SL201, SL600, SL601
12.1 STEM & DISASSEMBLY GLAND/YOKE
If the stem locks or “freezes”, causes can generally be attributed to dry worn packing or a dry yoke nut.
In either of these cases, the following service is required:
a) Unscrew gland nuts, remove the gland flange and bushing to expose stem packing and lantern ring
(where applicable). Replace stem packing if it is damaged. If the lantern ring is seized, completely
disassemble the stem and replace the lantern ring (where one is fitted).
b) Check lubrication of yoke nut. If it is dry, remove the yoke nut and determine if there is evidence of
seizure marks. If so replace it with a new yoke nut.
12.2 DISASSEMBLY OF STEM PACKING
It is important that prior to servicing, the valve be opened to its fullest extent and the line be totally
purged of any pressure (eye safety goggles should be worn). Partially unscrew nuts to reduce the
compression load on the stuffing box. Remove the stem packing or seals.
12.2.1 Stem Packing Replacement
1. Check tightness of valve operation to serve as a reference when re-tightening. Remove gland nuts and
the hook. Lift the gland up the stem clear away from the packing chamber.
2. Remove the defective packing rings or seals with a sharp tool or packing hook. Do not scratch or score
the machined surfaces of the stem or packing chamber.
3. Examine the machined surfaces of the stem and packing chamber. Remove any scratches, scoring or
burrs with an emery cloth or by hand filing. Clean the stem with a solvent soaked rag.
4. Count original number of rings and measure x-section thickness.
5. Order and then install new packing or seals.
6. When packing chamber becomes filled with packing (or in case of O-ring seal system the O-rings are
replaced), reassemble gland and gland flange. Alternate tightening gland flange nuts 1/4 turn at a
time until eyebolts begin to get tight. (If gland travels more than the height of one packing ring into
the packing chamber, insert one more ring and repeat step 6. until chamber is filled).
7. Compare valve operation to original tightness. If valve operation is considerably tighter than original
operating tightness, back off 1/4 turn on each gland nut & recheck tightness.
8. Several hours after a repacked valve has been returned to service, inspect the packing area to ensure
full compression, tight bolting and no leakage. Should leakage occur, tighten gland nuts at 1/4 turn
increments until leakage stops.
First remove the valve from the line. To prevent injury ensure that all fluid and
pressure is removed from the valve both upstream and downstream before removal
and disassembly. When removing drain or stem plug wear protective eye masks to
avoid injury.
