Flowserve Mark 3 Sealed Metallic Durco - Manual (Page 55)

MARK 3 USER INSTRUCTIONS ENGLISH 71569102 01-13
Page 55 of 72 flowserve.com
this tool Flowserve can often determine not only the
existence of a problem before it becomes serious, but
also the root cause and possible solution.
Modern vibration analysis equipment not only detects
if a vibration problem exists, but can also suggest the
cause of the problem. On a centrifugal pump, these
causes can include the following: unbalance,
misalignment, defective bearings, resonance,
hydraulic forces, cavitation and recirculation. Once
identified, the problem can be corrected, leading to
increased MTBPM for the pump.
Flowserve does not make vibration analysis
equipment, however Flowserve strongly urges
customers to work with an equipment supplier or
consultant to establish an on-going vibration analysis
program. See note 3 under figure 6-19 regarding
acceptance criteria.
6.9 Assembly of pump and seal
It is important that all pipe threads be
sealed properly. PTFE tape provides a very reliable
seal over a wide range of fluids, but it has a serious
shortcoming if not installed properly. If, during
application to the threads, the tape is wrapped over the
end of the male thread, strings of the tape will be
formed when threaded into the female fitting. These
strings can then tear away and lodge in the piping
system.
If this occurs in the seal flush system, small orifices can
become blocked effectively shutting off flow. For this
reason, Flowserve does not recommend the use of
PTFE tape as a thread sealant.
Flowserve has investigated and tested alternate
sealants and has identified two that provide an
effective seal, have the same chemical resistance as
the tape, and will not plug flush systems. These are
La-co Slic-Tite and Bakerseal. Both products contain
finely ground PTFE particles in an oil based carrier.
They are supplied in a paste form which is brushed
onto the male pipe threads. Flowserve recommends
using one of these paste sealants.
Full thread length engagement is required for all
fasteners.
Refer to figure 6-2 for recommended bolt
torques.
6.9.1 Power end assembly
The Mark 3A design has an optional oil slinger. If the
slinger was removed during disassembly, install a
new slinger [2541]. (See figure 6-29.)
Figure 6.28
Bearing installation 6.9.1.1
Mounting of bearings on shafts must be done in a
clean environment. Bearing and power end life can
be drastically reduced if even very small foreign
particles work their way into the bearings. Wear
clean gloves.
Bearings should be removed from their protective
packaging only immediately before assembly to limit
exposure to possible contamination. After removing
the packaging they should only come in contact with
clean hands, fixtures, tools and work surfaces.
The chart shown in figure 6-30 gives the SKF part
numbers for bearings in Flowserve Mark 3 pumps. Note
that the term “inboard bearing” refers to the bearing
nearest to the casing. “Outboard bearing” refers to the
bearing nearest to the motor. (See figure 6-29.)
Both bearings have a slight interference
fit which requires that they be pressed on the shaft with
an arbor or hydraulic press. Figure 6-20 identifies the
bearing fits. Even force should be applied to only the
inner race. Never press on the outer race, as the force
will damage the balls and races.
An alternate method of installing bearings is to heat
the bearings to 93 °C (200 °F) by means of an oven
or induction heater. With this approach the bearing
must be quickly positioned on the shaft.
Never heat the bearings above 110 °C (230 °F). To
do so will likely cause the bearing fits to permanently
change, leading to early failure.
a) Install the inboard bearing [3011] on the shaft
[2100].
Mark 3A and ANSI 3A design
The inboard bearing must be positioned against the
shoulder as shown in figure 6.29.
Mark 3 design
On Group 1 and Group 2 shafts, the inboard
bearing must be located as shown in figure 6.31.
On Group 3 shafts position the inboard bearing
against the shoulder.