Instruction Manual
D101642X012
ENVIRO-SEAL Sliding-Stem Valves
July 2017
7
Tightening Procedures
1. You will obtain maximum benefit from your ENVIRO
-
SEAL packing system when you tighten the packing flange nuts
and compress the Belleville springs to their “target load”. The target load is the point where the Belleville springs
are designed for optimum performance, when they are compressed to 85% of their maximum deflection, or nearly
flat. (Maximum deflection is when the springs are 100% compressed, or completely flat.)
To obtain the target load of 85% compression of maximum deflection, perform the following:
D
Tighten the packing flange nuts alternately and evenly, keeping the packing flange parallel with the valve flange
(see figure 3), until the Belleville springs are compressed 100% (or completely flat), as detected by a rapid increase
in nut torque.
D
For PTFE or Duplex packing, loosen each packing flange nut 1/2 turn (180
_
of rotation).
D
For Graphite ULF packing, loosen each packing flange nut 1/4 turn (90
_
of rotation).
The “target load” of 85% compression has now been reached.
2. Refer to the appropriate valve and actuator instruction manuals when connecting the valve to the actuator. Under
normal conditions, the packing nuts should not require retightening.
However, when servicing, if the springs do not remain at the target load of 85% compression, retighten the packing
box nuts according to step 1 above.
3. The “springs flat” procedure described above in steps 1 and 2 of Tightening Procedures is the preferred method of
adjusting ENVIRO
-
SEAL packing. However, for Graphite ULF packing, the torque values in table 7 can also be used as
a guideline for 85% spring compression. These values are based on generous lubrication of the packing studs and
nuts with anti
-
seize lubricant. Loosening of the packing flange nuts is not required when these torques are used.
Other Considerations
When retrofitting an existing packing system or repacking a valve with ENVIRO
-
SEAL packing that has been in service,
check the condition of the packing bore after you have removed the packing. An easy method for cleaning debris and
minor imperfections from the bore is to use a brake cylinder hone attached to an electric drill. This method will do a
good job of cleaning the packing bore without changing the dimension of the bore.
When you have completed this exercise, a good guideline to use in checking the condition of the packing bore is the
20/20 rule.
If less than 20% of the surface area of the bore is pitted and if there are no pits deeper than 0.020 inch, then
your packing should work as designed.
This does not need to be an exact measurement; visual inspection is adequate.
If the packing bore does not meet this criteria, however, you should replace the bonnet.
Note
This check is only valid for rotary ENVIRO
-
SEAL packing systems and sliding
-
stem ENVIRO
-
SEAL or HIGH
-
SEAL packing systems.
Parts Ordering
Each valve assembly is assigned a serial number that can be found on the valve body. Refer to this serial number when
contacting your
or Local Business Partner for technical assistance. When ordering replacement
