Leslie Controls CONTROL VALVES DLOS-2 & DDLOS-2 (150/300) - Manual (Page 4)

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SECTION III –
MAINTENANCE
To reduce maintenance time refer to proper
drawing and follow steps shown below for
applicable operation.
RENEWING
VALVE PLUG STEM
PACKING
(See Fig. 3, Fig. 4 and 5)
Renew valve plug stem packing if control valve
has been in service beyond normal maintenance
and packing shows signs of wear. Wear will be
indicated by leakage at the packing gland. Minor
leakage of graphite packing can be corrected by
tightening the packing flange.
Where LESLIE (BRAIDED TEFLON
GRAPHITE) packing is in use, additional
packing rings can be installed to overcome minor
leakage without dismantling the control valve or
breaking valve plug connection.
Shut down inlet and outlet stop valves and check
that valve body is not under pressure. Remove
nuts and lift packing flange and packing bearing
a sufficient height on valve plug stem to apply a
split packing ring around diameter of valve plug
stem. Lower packing bearing over the new ring,
lower packing flange and tighten sufficiently
with nuts to stop leakage.
To replace LESLIE “TEFLON” packing set or a
complete GRAPHITE 11 packing set, the control
valve must be dismantled.
Installation of Stem Packing
Stuffing box interior and valve plug stem must
be clean, smooth and free from imperfections
that may cause new packing to leak.
BRAIDED PTFE/GRAPHITE TYPE
PACKING
Figure 4 - Installation Sequence
1.
Place metal ring in stuffing box making sure
it bottoms in box followed by spring and
second metal ring. Install bottom Teflon
adaptor chevron, four Teflon packing
chevrons and top Teflon adaptor chevron in
accordance with Fig. 6.
2.
Install packing follower, packing flange and
nuts. Tighten stuffing box nuts until
follower bottoms on bonnet.
PTFE CHEVRON TYPE PACKING
Figure 5 - Installation Sequence
CAUTION!
Over-tightening of the packing flange
adjustments can cause erratic operation of
the valve.