ET Valve
Instruction Manual
Form 5081
June 2002
5
LUBRICATOR
LUBRICATOR/ISOLATING VALVE
10A9421-A
AJ5428-D
A0832-2/IL
Figure 2. Lubricator and Lubricator/Isolating Valve (Optional)
Packing Maintenance
Note
For valves with ENVIRO-SEAL
packing, see the Fisher instruction
manual, ENVIRO-SEAL Packing
System for Sliding-Stem Valves, Form
5306, for packing instructions.
For valves with HIGH-SEAL packing,
see the Fisher instruction manual,
HIGH-SEAL Live-Loaded Packing
System, Form 5263, for packing
instructions.
Key numbers refer to figure 3 for PTFE V-ring
packing and to figure 4 for PTFE/composition
packing, unless otherwise indicated.
For spring-loaded single PTFE V-ring packing, the
spring (key 8) maintains a sealing force on the
packing. If leakage is noted around the packing
follower (key 13), check to be sure the shoulder on
the packing follower is touching the bonnet. If the
shoulder is not touching the bonnet, tighten the
packing flange nuts (key 5, figure 14) until the
shoulder is against the bonnet. If leakage cannot be
stopped in this manner, proceed to the Replacing
Packing procedure.
If there is undesirable packing leakage with other
than spring-loaded packing, first try to limit the
leakage and establish a stem seal by tightening the
packing flange nuts.
If the packing is relatively new and tight on the stem,
and if tightening the packing flange nuts does not
stop the leakage, the valve stem may be worn or
nicked so that a seal cannot be made. The surface
finish of a new valve stem is critical for making a
good packing seal. If the leakage comes from the
outside diameter of the packing, the leakage may be
caused by nicks or scratches around the packing
box wall. If performing any of the following
procedures, inspect the valve stem and packing box
wall for nicks and scratches.
Replacing Packing
1. Isolate the control valve from the line pressure,
release pressure from both sides of the valve, 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, and 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.
2. Disconnect the operating lines from the actuator
and any leak-off piping from the bonnet. Disconnect
the stem connector, then remove the actuator from
the valve by unscrewing the yoke locknut (key 15,
figure 14) or the hex nuts (key 26, figure 14).
3. Loosen the packing flange nuts (key 5, figure 14)
so that the packing is not tight on the valve stem.
Remove any travel indicator parts and stem locknuts
from the valve stem threads.
WARNING
To avoid personal injury or property
damage caused by uncontrolled
movement of the bonnet, loosen the
bonnet by following the instructions in
the next step. Do not remove a stuck
bonnet by pulling on it with equipment
that can stretch or store energy in any
other manner. The sudden release of
stored energy can cause uncontrolled
movement of the bonnet.
Note
The following step also provides
additional assurance that the valve
body fluid pressure has been relieved.