Fisher-Rosemount Design CV500, Инструкция по эксплуатации

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Design CV500
8
Packing Maintenance
Key numbers refer to figure 11 for 3 through 8-inch
sizes and to figure 12 for 10 and 12-inch sizes unless
otherwise indicated.
Note
For the ENVIRO-SEAL packing system,
refer to the Parts List section for retrofit
kits, parts kits, and individual parts (see
figures 13 and 14). Refer to separate
ENVIRO-SEAL instruction manual for
maintenance instructions.
Standard ENVIRO-SEAL packing
systems can be used in vacuum service
with packing rings in the standard
orientation. It is not necessary to reverse
the ENVIRO-SEAL PTFE packing rings.
Stopping Leakage
All maintenance procedures in this section may be
performed with the valve body (key 1) in the line.
For packings other than spring-loaded packing,
leakage around the packing follower (key 14) can be
stopped by tightening the packing flange nuts (key 16).
If leakage cannot be stopped in this manner, replace
the packing according to the Replacing Packing
procedure.
If the packing is relatively new and tight on the drive
shaft (key 3), and if tightening the packing nuts does
not stop leakage, it is possible that the shaft is worn or
nicked so that a seal cannot be made. If the leakage
comes from the outside diameter of the packing, it is
possible that the leakage is caused by nicks or
scratches on the packing box wall. Inspect the shaft
and packing box wall for nicks or scratches when
performing the following procedures.
Replacing Packing
Note
If the valve has ENVIRO-SEAL
live-loaded packing installed, see the
manual entitled ENVIRO-SEAL Packing
System for V-Line and edisc Rotary
Valves.
This procedure may be performed without removing
the actuator from the valve if adding
PTFE/composition packing rings as a temporary
measure. However, the actuator must be removed if
replacing any other kind of packing or if the metal
packing parts (keys 14, 17, and, if used, 18) need to
be replaced.
1. Isolate the control valve from the line pressure,
release pressure from both sides of the valve body,
and drain the process media from both sides of the
valve. If using a power actuator, also shut-off all
pressure lines to the power actuator, release all
pressure from the actuator. Use lock-out procedures to
be sure that the above measures stay in effect while
you work on the equipment.
CAUTION
To avoid increased leakage, increased
valve component wear or possible
damage to the valve body, ball, shaft,
and bearings resulting from a sharp
blow to the shaft, use a wheel puller to
separate the actuator parts from the
drive shaft.
Do not drive the actuator parts off the
drive shaft since this could move the
valve bearings, shaft, and ball away from
proper alignment, causing improper
seating of the ball. Such misalignment
may result in damage to valve
components if the valve is returned to
service without disassembly and
inspection of the valve ball alignment.
2. If necessary, remove the cap screws (key 25) and
hex nuts (key 26). Then remove the actuator while
referring to the actuator instruction manual for
assistance.
3. Remove the packing nuts (key 16). For 3 through
8-inch sizes, remove the packing follower (key 14). For
10 and 12-inch sizes, remove the packing flange (key
45) and then remove the packing follower (key 14).
4. Remove the old packing rings (key 13), packing
box ring (key 17), and, if used, the lantern ring (key
18). Do not scratch the valve shaft or packing box wall;
scratching these surfaces could cause leakage. Clean
all accessible metal parts and surfaces to remove
particles that would prevent the packing from sealing.
5. Whenever you are installing new packing, be sure
the ball (key 2) is closed while you install and tighten
the new packing. Install the new packing rings and
packing box ring by stacking the parts as shown in
figure 6. Make sure split rings are arranged so that the
splits do not line up to form a leak path. Then slide the
stack into the packing box as far as they will go while
being careful to avoid trapping air among the rings.
6. Install the packing follower (key 14), and, for 10 and
12-inch sizes, also install the packing flange (key 45).
Install the nuts (key 16), and tighten them far enough
to stop leakage under normal conditions.
7. Mount the actuator while referring to the actuator
mounting procedures in the actuator instruction