Installation
of Braided Packing
Packing the Pump Correctly:
The importance of packing the pump correctly cannot be overemphasized.
Many packing failures are due to the incorrect installation
of the packing. The following steps have been devised
to ensure effective installation of packings on pumps.
1. Remove all the old packing from the stuffing box.
Clean box and shaft thoroughly and examine shaft sleeve
for wear and scoring. Replace shaft sleeve in wear is excessive.
2.
Choosing the correct cross-section of packing.
To determine the correct ring size:
A. Measure the diameter of the shaft (inside the stuffing box
area, if possible.)
B. Measure the diameter of the stuffing box (to give the O.D.
of the ring.)
C. Subtract the I.D. measurement from the O.D., measure and divide
by two. The result is the required cross section.
3. Cutting packing into rings.
Figure 1: Hold the packing tightly on the mandrel, but do not
stretch excessively, and cut the ring(s).

Figure 2: Multiple
rings can be Butt Cut / 90? ?X? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!? ?xX? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!H!
Figure 3: Individual
rings can be Skive Cut / 45? ?X? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!? ?xX? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!H!
The best way to cut packing rings
is to cut them on the mandrel with the same diameter as the
shaft in the stuffing box. If there is no wear, rings can be
cut on the shaft outside the stuffing box.
Insert one ring at a time into
the stuffing box, making certain it fits the packing space properly.
Each additional ring can be cut in the same manner, or the first
ring can be used as a master from which the balance of the rings
are cut.
If the Butt Cut rings are cut
on a flat surface, be certain that the side of the master rings,
and not the I.D. or O.D. surface, is laid on the rings to be
cut. This is necessary so that the end rings can be reproduced.
When cutting Skive, diagonal joints,
use a maple miter board so that each successive ring can be
cut at the correct angle.
It is necessary that rings be
cut to the correct size. Otherwise, service life is reduced.
4. Install one ring at a time. Make sure the
packing ring is clean and has not picked up any dirt in handling.
If needed, lubricate the shaft and inside of the stuffing box.
Packing rings should be firmly
seated in the stuffing box one at a time using a tamping tool.
Figure 4: Joints of successive
packing should be staggered at 90? ?X? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!? ?xX? ?X? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X? ?X!? ?X? ?X8!H!
5.
After the last ring is installed. Put the gland
in place and take up bolts finger tight or very slightly snugged
up. Do not jam packing into place with excessive gland loading.
Start the pump and take up bolts until leakage is decreased
to a tolerable minimum. Make sure gland bolts are adjusted evenly.
Stopping leaking entirely at this
point will cause the packing to burn up.
6. Allow packing to leak freely when starting up a newly packed
pump. Excessive leakage during the first hour
of operation will result in a better packing job over a longer
period of time. Take up gland bolts gradually as the packing
seats to a tolerable level of 10 to 12 drops per minute per
inch of shaft diameter. Never
try to stop leakage entirely, unless packing manufacturer indicated
that it is safe to do so.
7. When specified by the pump manufacturer, provide means of
lubricating the shaft and the packing through the lantern ring
by supplying water, oil, grease or liquid handled in the pump.
Fittings for this purpose are standard on many pumps.
8. If the stuffing box has a lantern ring ,
make sure that the lantern ring, as installed, is slightly behind
the fluid inlet so that it will move under the inlet as the
follower pressure is applied.See Figure 5
9.
On both centrifugal and reciprocating pumps,
about 70% of wear is on the outer two packing rings nearest
the gland. However, each additional ring does throttle some
fluid pressure. On most equipment, there must be enough rings
so if one fails, another does the sealing, and the machine need
not be shut down.
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