Fisher Control-Disk Instruction Manual page 10

Control-Disk Valve
June 2017
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 10 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.
2. Remove the actuator per instructions in separate actuator instruction manuals, then remove the cap screws and
nuts (keys 35 and 36). Remove the clamp (key 130, figure 3) if the strap (key 131, figure 3) is used.
3. Remove the packing flange nuts and the packing flange (key 26) if used and pull out the packing follower (key 25).
4. Remove the anti‐blowout ring (key 40) from the drive shaft (key 10).
5. Remove the old packing rings (key 24) and, if used, the packing washers (key 31). Carefully avoid scratching the
shaft or packing box wall to avoid damage that could cause leakage around the shaft. Clean all accessible metal
parts and surfaces to remove particles that would prevent the packing from sealing.
WARNING
Do not lubricate parts when used in oxygen service, or where the lubrication is incompatible with the process media. Any
use of lubricant can lead to the sudden explosion of media due to the oil/oxygen mixture, causing personal injury or
property damage.
10
Instruction Manual
D103298X012