Emerson VANESSA 30,000 Series Installation, Operation And Maintenance Manual page 10

VANESSA SERIES 30,000 TRIPLE OFFSET VALVE (TOV)
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
Packing flushing
The packing flushing option is obtained
by the introduction of a tapped hole that
communicates directly to the packing box in the
neck of the valve via a lantern ring. This option
can be used to monitor the rate of emission of
the line fluid toward the atmosphere. This flush
tap may also be used to capture and evacuate
line fluid to prevent any atmospheric loss, with
the lantern ring and split packing configuration
acting as a double block and bleed unit.
A suitable fluid may also be introduced via the
packing flush tap into the packing area so as
to eliminate any possible fugitive emissions
(see figure 10). By keeping the fluid pressurized
at a pressure that is higher with respect to
the line pressure, the passage of any line fluid
towards the atmosphere can be effectively
blocked giving the valve excellent fugitive
emissions control. However, the fluid used
must be compatible with the line fluid as it may
have the possibility of finding its way into the
line as well as toward the atmosphere.
As with the bearing flushing option this
may also be used to introduce a lubricant
compatible with the process.
The selection of the most appropriate type
of lubricant for flushing is under the user's
responsibility. Contact your nearest Emerson
sales office for further details or process
specific information.
FIGURE 11
5.2 Live loaded packing
The live loaded packing option is designed to
supplement the standard characteristics of the
Vanessa valve packing. This option guarantees
a constant compression of the packing set.
The fact that the packing is subject to a near
constant force supplied by the Belleville springs
reduces the maintenance frequency required by
the packing (see figure 11).
Care should be given in replacing the Belleville
springs as their order (parallel or in series)
should be understood and kept.
The packing flange nuts should be tightened in
accordance with Table 1.
The drawing in figure 11 shows typical set ups
for the live loaded packing option.
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