Instruction Manual

Instruction Manual
D102136X012
KALREZ System - Sliding-Stem Valves
May 2011
4
Figure 2. KVSP System Tightening Procedure
90AY012600A
B2459
FLAT CONDITION
COMPRESSED
HEIGHT
UNCOMPRESSED
FREE HEIGHT
The following tightening procedure will change the final loading force to about 1/2 of a fully compressed disk spring.
1. Hand tighten the gland nuts on the Belleville disk springs and measure the uncompressed or free height as shown
in figure 2.
2. Fully compress the Belleville disk springs alternately and evenly to the flat condition. The flat condition will be
evident by a sharp increase in the applied nut torque. Note that there may appear to be space left between the
springs; this is due to friction between the springs. Measure the compressed height. See figure 2.
3. Back off the disk spring load by 1/3 or 33% of the difference between (1) the free spring height and (2) the fully
compressed spring height.
Other Considerations
When retrofitting an existing packing system or repacking a valve with KALREZ 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.
If any visible pits or defects remain in the packing bore, the bonnet should be replaced.