Page 505
T31 SERIES
Operation
3.
CLOSE COUPLED PUMPS
FLEXIBLE COUPLED PUMPS
A.
Rotation
B.
Inlet and Outlet Locatrions
C.
Foreign Material
D.
Electrical
E.
Adjustments
F.
Cooling Water
G.
Priming
H.
Starting
I.
Stopping
3A Rotation
The standard direction of rotation of the
pump is right handed, or clockwise when
looking at the motor end of the pump.
A rotation arrow, refer to Figure 3-1,
is located on the pump to indicate the
correct direction of rotation.
Operating the pump in reverse will
cause substantial performance varia-
tions and can damage the pump.
Always confirm correct motor rotation
prior to connection of the coupling. If this
is not possible, or a final rotation check
is being performed:
1. Jog the motor briefly.
2. Observe rotation as the unit comes to
a stop.
3. Rotation should be in the direction of
the arrow.
If the motor operates in the wrong direc-
tion:
1. Interchange any two leads on a three
phase motor.
2. On a single phase motor,
change the leads as indicated on the
connection box cover. Some single
phase motors may not be reversible.
3B Inlet and Outlet Locations (Refer
to Figure 3-1)
The pump inlet is located on the end
farthest from the motor. The discharge
or “outlet” can be on the top, side, or
bottom depending on the model and
construction of the pump. Normal dis-
charge position is on top.
3C Foreign Material
All regenerative turbine pumps have
close running clearances in order to
maintain efficiency. Take extra precau
-
tions to insure that no foreign material
larger than 25 microns or .001 inches is
allowed to pass through the pump. Even
particles of this size can damage the
pump if allowed to continue. Regenera-
tive turbine pumps are not designed for
slurries.
Large particles, weld spatter, and other
material found in new
piping systems will bend the impeller
vanes and can sometimes lock up the
pump. If a new pump does not operate
properly, the first thing to check for is
damage from foreign material.
3D Electrical
It is important to be aware of and follow
the appropriate local and national
electrical codes. Do not make wiring
alterations that can affect motor rotation
without reconfirming correct rotation.
Select starter heaters and wiring for the
maximum current the motor can use at
full service factor loads. Regenerative
turbine pumps will typically use extra
power for a period until they run in. This
can take three to four weeks depending
on the duty cycle. During this period,
impellers are finding their hydraulically
balanced position.
3E Adjustments
No adjustments are required or advis-
able on new pumps. Because of the
close fits in regenerative turbine pumps,
it is not uncommon for the pump to be
difficult to turn over by hand after they
have been allowed to dry out inside.
New pumps from the factory are tested
using rust inhibitors to preclude this
possibility. On site system flushing may
remove these inhibitors and subject
the pump to the risk of lock up, if it is
allowed to dry out. In this case, do the
following:
1. Fill the pump with fluid.
2. Loosen the thrubolts exactly one turn.
3. Jog the pump momentarily
using the on/off buttons if so
equipped.
4. This should “break” the impeller loose
without damage, unless foreign mate-
rial has entered the pump.
5. If possible, spin the pump (or operate
with minimal or zero discharge
pressure) while the thrubolts are
retightened exactly one turn.
This will flush residue from the close
fitting impeller surfaces.
Because of the large areas of close
fitting surfaces inside these pumps,
it takes only microscopic residue to
produce resistance to rotation. Once
loosened, this material is quickly dis-
persed and the impellers will find their
hydraulic center. If these procedures
have been followed, no damage will
have resulted from "breaking loose" the
impeller.
3F Cooling Water
When the pump is used to pump hot
fluids, consideration should be given
to cooling the seals and/or selecting
materials that will give satisfactory seal
life. The actual temperature at the seal
faces, the most critical area, will always
exceed the surrounding fluid tempera
-
ture. If seal flushing lines have not been
installed, heat can build up in the seal
faces to a degree that may destroy the
fluid film necessary to prevent rapid
wear. In some cases it is necessary to
cool the seal flushing fluid. Refer to the
seal manufacturers charts for guidance
or to selection data in the MTH catalog
anytime fluids can reach or exceed their
boiling point.
3G Priming
Pumps should not be operated
unless they are completely filled with
liquid. Damage to parts of the pump that
depend on liquid for their lubrication can
occur. Impellers can seize quickly when
a pump is run dry. Without lubrication,
seal faces can be damaged from heat
buildup.
Pumps can be easily primed with a
vacuum pump. An ejector or liquid ring
vacuum pump is recommended for this
purpose because they are not damaged
if liquid enters them.
2E3 Piping Size
In general, inlet and outlet pipe sizes
should be equal to or larger than those
of the pump.
This should not, however, be the de-
termining factor. Many things including
installation and operating costs are
involved in the decision. Careful use of
the pipe and fitting friction loss tables
as shown in the Hydraulic Institute
manual along with the appropriate pump
performance curve should be the basis
for judgments.
2F Typical Installation (Refer to Fig-
ure 2-5)
Figure 2-5 shows a typical pump instal-
lation, note the use of pipe hangers
and support and the position of piping,
valves, and components.
Figure 3-1
Outlet
Rotation
Inlet
