¡ï Before fixing new packing, the used packing
should be removed completely with special tools,
and the box of packing should be mopped clean.
Observe carefully tosee if there is any part
within the box of being off-centre. In case of
failure to be up to the required standard,the
box should be repaired or replaced.
¡ï Select
the right packing to seal the fluid. Cut the
exactly rigs with the packing cutter. If the
cutter is not available, proceed as follows:the
cutting length of the rings L=(shaft diameter
D+packing width S) X 1.07X ~ . In principle, for
rotating shafts,to cut the packing straight
in90¡ã ;but in valves,slanted cut is more
recommend,about 45¡ã¡£
¡ï While fitting
cross-sections of packings should be used for
valves, preferably prepressed rings, a packing
cross section with a slignt undersize (abt.0.3mm
to 0.6mm)isrecommended for pumps.The required
leakage gap ensures the necessary higher
starting leakage for lubrication and dissipation
of friction heat.
¡ï Cut packing rings should
be installed with the cut ends staggered by 90¡ã
each layer. The rings should be carefully opened
axially and radially just sufficient for them to
be pushed on the shaft. If the rings are opened
they can suffer damage through buckling.
¡ï
Continue to fit rings in the stuffing box until
the gland has thread available to either about
25% the packing thickness in the case of valves,
or about 50% in the case of pumps.
¡ï In order
to enhance the tight-sealing performance, it is
preferential to select two or more gasket of
cushion plates, and mix them for the said
fixing.
¡ï Press the rings home with the grand
and tighten the nuts by hand. In order to obtain
a uniform and controlled pretension of the
packing, we recommend the use of a torque wrench
or a similar power measuring device.
¡ï Before
putting into regular operation, try it under
zero-load, and observe if there is anything
abnormal. After putting into normal operation,
it is still necessary to observe carefully to
see if there is any serious leakage due to lack
of compactness, or if there is sudden
friction-heat and the danger of ring burning as
a result of over
compactness.
