Foil wrapped packing sets are furnished with soft rings of fibrous
packing which are placed between the hard metallic rings in the
locations shown in the diagrams. These rings help to furnish lubrica-
tion during the run-in period. Being soft, they are more sensitive to
compression loads and care must be taken during the adjustment
period.
Follow these steps:
1) With the packing gland slid back against the splash collar, place a
ring of packing on the shaft sleeve and enter it carefully into the
seal chamber. Install a second ring, and a third ring if appropriate.
Stagger all joints at 90° intervals. Follow the proper sequence if
hard and soft rings are used. Using a packing tamper in the seal
chamber, slide the packing gland up on the packing gland studs,
put on the gland stud nuts and tighten them evenly and firmly, seat-
ing the packing rings firmly against the bottom of the seal chamber.
This should make the shaft difficult to turn by hand.
2) Back off the gland stud nuts and the packing gland and remove the
packing tamper.
3) If a lantern ring is to be used, check the packing and pump
specifications to determine its position and install it with the proper
number of rings of packing between it and the bottom of the seal
chamber.
4) Continue to pack the pump with packing rings placed on the shaft
sleeve until the seal chamber is nearly full and seat them firmly as
above. Packing ring joints should be staggered at 90° intervals.
5) Back off the gland stud nuts to finger tightness.
6) Rotate the pump shaft by hand to be sure it is not locked.
7) Final adjustment of the packing compression must be made with
the pump running. Start and stop the pump several times to begin
the running-in period. Allow sufficient leakage to assume good
lubrication during the adjustment. Pull up the gland stud nuts
1
/8
turn at a time. Allow a running in period between adjustments.
Continue adjustment until the desired leakage control is reached.
The minimum leakage rate depends on a number of things: liquid
pumped, packing used, temperature, seal chamber pressure, and
the condition of the pump. In any case, some leakage is necessary
to both lubricate and cool the packing. Minimum rates may vary
from a few drops per minute to as much as
1
/2
pint per minute.
8) As the packing wears in service, the gland should be readjusted to
maintain the minimum leakage.
9) After the gland has been taken up to full travel, an additional ring
of packing may be placed in the seal chamber. When the gland
has again been taken up to full travel the seal chamber should be
repacked completely.
USUAL CAUSES OF PACKING FAILURE AND EXCESSIVE SEAL
CHAMBER LEAKAGE
1) Packing has not been installed properly.
2) Packing used is not suitable for the temperature and pressure
involved or may be subject to attack by liquid handled.
3) Inner rings are not thoroughly seated in the seal chamber so that
outer rings are carrying all the load.
4) Dirt and foreign particles in seal chamber are causing rapid scor-
ing of shaft sleeve.
5) Seal chamber cooling water not turned on.
6) Packing gland pulled up too tight.
When ordering additional packing sets, always refer to packing set num-
ber and to pump serial number.
INSTALLATION OF STANDARD MECHANICAL SEALS
Clean, careful, and correct installation of the mechanical seal is
essential to successful mechanical seal operation. Cleanliness and
accuracy of setting cannot be overemphasized.
For instructions on pump disassembly and assembly see the instruc-
tion manual relating to the specific pump type.
A correct mechanical seal drawing is furnished with each pump and
the mechanical seal setting dimension is given on this drawing.
Use the setting for the specific pump type in which the installation is
being made.
The pump is first assembled according to the applicable assembly
instructions through the step of proper impeller adjustment.
The mechanical seal rotary unit must be properly located in relation
to the face of the pump seal chamber in order to establish the proper
seal spring tension and resultant proper force on the seal faces. An
error in setting of more than several thousandths of an inch may well
cause seal failure by excessive or insufficient seal face pressure.
INSTALLATION OF SINGLE INSIDE SEALS
To make the seal installation, with the pump partially assembled as
noted above, scribe a mark on the shaft sleeve (10) exactly in line
with the face of the pump seal chamber (Note 1). The impeller (3),
and casing back cover (22) are now removed from the pump. If the
mark causes roughness on the shaft sleeve remove the burr carefully
with crocus cloth. Any roughness on the shaft sleeve may damage
the mechanical seal shaft packing when the seal is assembled.
Referring to the mechanical seal drawing, determine the proper “D”
dimension for the seal and pump type. Measure carefully from the
mark which you have made on the shaft sleeve and make a new
mark on the shaft sleeve, towards the pump end, exactly to this
dimension.
If the mechanical seal insert is of the clamped-in style, put the
mechanical seal gland (300) on the pump shaft and slide it back
against the flinger. Put one mechanical seal gland insert gasket
(325), the gland insert (315) and the other gland insert gasket (326)
on the shaft. Make sure that the lapped face of the gland insert is
towards the seal chamber.
Flexibly mounted inserts are two types, depending on the service of
the pump. The insert may be of rectangular cross section grooved for
an o-ring or it may be of L-shaped cross-section used with a Teflon
mounting ring.
To position the o-ring mounted insert, lubricate the inside of the
mechanical seal gland. Place the o-ring in the groove of the insert
and carefully slide the insert into position. Be careful not to damage
the o-ring. Make sure that the lapped face of the insert faces towards
the pump.
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