Goulds Pumps 3498 - IOM - Manual (Page 41)

SEALING INFORMATION
WATER LUBRICATION
Only a sufficient volume of sealing liquid to create a
definite direction of flow from the stuffing box inward to
the pump casing is required, but the pressure is important.
Apply seal water at a rate of 0.5 - 1.0 GPM, at 15 -20 PSI
above stuffing box operating pressure.
We recommend that piping supplying sealing liquid to
stuffing box be sized to supply a sufficient volume of water
at the required pressure, based on the location of the pump
(or pumps) with respect to the liquid source. A small pipe
can be utilized for the connection to the stuffing box. A
valve should be installed to adjust and regulate sealing
liquid and a gauge installed to check pressure to the box.
External sealing liquid should be adjusted to the point
where the packing runs only slightly warm, with a very
slow drip from the stuffing box. Excess pressure from an
external source can be very destructive to packing. More
pressure is required, however, for abrasive slurries than for
clear liquids. Examination of the leakage will indicate
whether to increase or decrease external pressure. If slurry
is present in the leakage, increase the pressure until only
clear liquid drips from the box. If the drippage is corrosive
or harmful to personnel, it should be collected and piped
away.
A common error is to open the external piping valve wide
and then control the drippage by tightening the packing
gland. Actually, a combination of both adjustments is
essential to arrive at the optimum condition. The life of
packing and sleeve depends on this careful control more
than any other factor.
GREASE LUBRICATION
Pump stuffing boxes are also suitable for grease
lubrication. Several types of grease lubrication are
available. When using a grease lubricator, grease pressure
to the stuffing box should be equal to the pump discharge
pressure.
PACKING
Pumps are normally shipped with the packing set loose.
All packings used are the highest grade material. Before
pump is put into operation, check the condition of the
packing. If pump is installed within 60 days after shipment,
the packing will be in good condition with a sufficient
supply of lubrication.
If pump is stored for a longer period, it may be necessary to
repack the stuffing box. In all cases, however, we recommend
an inspection of the packing before pump is started.
The standard packing is a soft, square, non-asbestos fiber
impregnated with oil and graphite. A soft well-lubricated
packing reduces stuffing box resistance, and prevents
excessive wear on the shaft or shaft sleeve. Many brands of
packing on the market have the desired qualities. For
specific recommendations, consult the factory.
When a pump with fiber packing is first started, it is
advisable to have the packing slightly loose without
causing an air leak. As pump runs in, gradually tighten the
gland bolts evenly. The gland should never be drawn to the
point where packing is compressed too tightly, and no
leakage occurs. This will cause the packing to burn, score
the shaft or shaft sleeve, and prevent liquid from circulating
through the stuffing box, cooling the packing. The stuffing
box is improperly packed or adjusted if friction in the box
prevents turning the rotating element by hand. A properly
operated packed stuffing box should run lukewarm with a
slow drip of sealing liquid. After the pump has been in
operation for some time and the packing has been
completely run-in, drippage from the stuffing box should
be at least 40 to 60 drops per minute.
This will indicate proper packing and shaft sleeve
lubrication and cooling.
NOTE: Eccentric operation of the shaft, or sleeve,
through the packing could result in excess leakage
that cannot be compensated for. Correction of this
defect is very important.
Packing should be checked frequently and replaced as
service indicates. Six months might be a reasonable
expected life, depending on operating conditions. It is
impossible to give any exact predictions. A packing tool
may be used to remove all old packing from the stuffing
box. Never reuse old and lifeless packing or merely add
some new rings. Make sure that the stuffing box is
thoroughly cleaned before new packing is installed. Also
check the condition of the shaft or sleeve for possible
scoring or eccentricity, making replacements where
necessary.
New packing 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 so they are not in line. The
joints should be kept toward the upper side of the shaft and
should be at about a 90° angle 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.
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3498 IOM 12/04