Xylem 8100 Series Centrifugal Pumps AC2515 REV.C - Manual (Page 26)

or sleeve for possible scoring or eccentricity,
make replacements where necessary.
New packing (non-asbestos) should be
placed carefully into the stuffing box. If
molded rings are used, the rings should be
opened sideways and the joints pushed into
the stuffing box first. The rings are installed
one at a time, each ring seated firmly and the
joints staggered at about a 90° rotation from
each preceding joint.
If coil packing is used, cut one ring to
accurate size with either a butt or mitered
joint. An accurately cut butt joint is superior to
a poor fitting mitered joint. Fit the ring over
the shaft to assure proper length. Then
remove and cut all other rings to the first
sample. When the rings are placed around
the shaft a tight joint should be formed. Place
the first ring in the bottom of the stuffing box.
Then install each succeeding ring, staggering
the joints as described above, making sure
each ring is firmly seated.
Make sure the seal cage is properly located
in the stuffing box under the sealing water
inlet. The function of the seal cage is to
establish a liquid seal around the shaft,
prevent leakage of air through the stuffing
box and lubricate the packing. If it is not
properly located it serves no purpose.
Mechanical Seals
General instructions for operation of the
various mechanical sealing arrangements are
included below. It is not feasible to include
detailed instructions for all mechanical seals
in this booklet because of the almost
unlimited number of possible combinations
and arrangements. Instead, seal
manufacturer’s instructions will be included
as a separate supplement to this book, where
required.
a. Mechanical seals are precision products
and should be treated with care. Use
special care when handling seals. Clean
oil and clean parts are essential to prevent
scratching the finely lapped sealing faces.
Even light scratches on these faces could
result in leaky seals.
b. Normally, mechanical seals require no
adjustment or maintenance except routine
replacement of worn or broken parts.
c. A mechanical seal which has been used
should not be put back into service until
the sealing faces have been replaced or
relapped. (Relapping is generally
economical only in seals two inches in
size and above.)
Four important rules which should always be
followed for optimum seal life are:
1. Keep the seal faces as clean as possible.
2. Keep the seal as cool as possible.
3. Assure that the seal always has proper
lubrication.
4. If seal is lubricated with filtered fluid, clean
filter frequently.
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