Instruction Manual
D103302X012
A81 Valve
January 2011
10
For valves with the ENVIRO‐SEAL packing system:
Optimum performance of the ENVIRO‐SEAL packing system is obtained when the Belleville springs are tightened to
their “target load.” The target load is the point where the springs are compressed to 85% of their maximum deflection,
or nearly flat. Maximum deflection is when the springs are 100% compressed, or completely flat.
Under normal conditions, the packing nuts should not require re‐tightening. However, when servicing, if the springs
do not remain at the target load of 85% compression, retighten the packing box nuts according to the following
procedure:
1. Tighten the packing flange nuts alternately and evenly, keeping the packing flange parallel with the valve flange
(see figure 4), until the Belleville springs are compressed 100% (or completely flat).
D
For PTFE packing,
loosen each packing flange nut one half turn (180
_
of rotation).
D
For Graphite packing,
loosen each packing flange nut one quarter turn (90
_
of rotation).
The target load of 85% compression has now been reached. If leakage continues, replace the packing components as
described in the following procedures.
Replacing the Packing
To replace the packing, the actuator must be removed. Also, the valve should be removed from the pipeline to allow
proper readjustment of the disk position.
WARNING
The edges of a rotating disk have a shearing effect that may result in personal injury. To help prevent such injury, stay clear
of the disk edges when rotating the disk (key 3).
CAUTION
Damage to the disk (key 3) may occur if the disk is not closed when the valve is being removed from the pipeline. If
necessary, apply operating pressure to the actuator temporarily to retain the disk in the closed position while removing the
valve from the pipeline.
For valves with PTFE or graphite packing:
Key numbers in this procedure are shown in figure 9 unless otherwise indicated.
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 shutoff all pressure lines to the power
actuator, release all pressure from the actuator. Use lock‐out procedures to be sure the above measures stay in
effect while you work on the equipment.
CAUTION
When removing the actuator in the following step, use a wheel puller to separate the actuator parts from the valve shaft.
Do not drive the actuator parts off the valve shaft because this could damage valve trim components.
