stem-stuffing, stem-gland, and gland-stuffing box
clearances.
If GFY is not available, you can install a ring of
conventional packing as anti-extrusion rings.
However, the use must be temporary. At the earliest
opportunity, disassemble, inspect, and repack the valve
GFY packing, figure 15-25, is a severe service
packing ideal for use in difficult fluid-handling
applications. It is unaffected by the most destructive
corrosive fluid substances. It will withstand extreme
temperatures of over 1000F encountered in valve
stuffing boxes. GFY packing is self-lubricating. It has
allows tight packing adjustment to make leakage almost
Figure 15-25.--Graphite filament yarn.
nonexistent. It also provides maximum protection
against stem scoring. This packing greatly reduces
passes through the stuffing box. Inspect the interior of
system fluid loss, maintenance, and downtime to
the stuffing box itself. Take whatever steps you can to
provide longer, trouble-free valve life. GFY is
ensure that the packing will make contact with the
available in sizes from l/8 inch to 1 inch square on
straightest, smoothest possible surface. (You may have
spools.
to have the shaft repaired and refinished, or replaced.)
NOTE: Regardless of how good the packing
GASKETS
material may be, if the surface of the shaft passing
through the stuffing box is scored or damaged in any
At one time, fixed steam joints could be
way, the packing will not last long. When replacing
satisfactorily sealed with gaskets of compressed
packing, carefully inspect the shaft in the area where it
asbestos sheet packing (fig. 15-26, view A). However,
Figure 15-26.--Fixed joint gaskets. A. Sheet gaskets. B. Serrated-face metal gasket. C. Spiral-wound metallic gasket.
15-23