Xylem IMDWT R02 Model DWT Deep Well Turbine Pumps - Manual (Page 6)

6
Uncontrolled Long Term Storage Preparations
When applicable to the pump, storage periods over six
months require the preceding storage procedure and
storage preparation plus the following:
Inspect the lube oil piping and either fill the piping with
rust preventative oil, or re-coat the piping periodically to
prevent corrosion.
Place 10 pounds (4.5 kg) of moisture absorbing desiccant
or 5 pounds (2.3 kg) of vapor phase inhibitor crystals
near the center of the pump. If the pump is assembled,
place an additional one pound (0.5 kg) in the discharge
nozzle securely fastened to the discharge elbow.
Install a moisture indicator near the perimeter of the
pump. Cover the pump with 6 mil. (0.15 mm) minimum
thickness black polyethylene or equal and seal it with
tape. Provide a small ventilation hole approximately
½ inch (12 mm) diameter.
Provide a roof or shed shelter to protect from direct
exposure to the elements.
GENErAL dESCrIPTIoN
The model DWT pump is a vertical turbine lineshaft
pump, which is designed to meet wide ranges of service
with maximum dependability. See Figure 1 for open
lineshaft pump and Figure 2 for enclosed lineshaft pump.
Drivers
Hollow shaft motors or right angle gear drives, are often
used with a separate head shaft through the driver and
connected to the pump by a threaded coupling.
Discharge Head
The discharge head is either a cast iron head or a
fabricated Steel head. Ports are provided for connecting
the pressure gauge, stuffing box bypass return and
lubricator connections. The driver support portion of the
discharge head is designed with large windows for easy
stuffing box or tension plate adjustment. The windows
are covered with coupling guards for safe operation.
Column
Threaded or flanged column construction provides
positive shaft and bearing alignment. Bearings are spaced
to provide vibration free operation below the shaft. This
will insure long bearing life and reduced shaft wear. For
open lineshaft, the shaft is supported within the column
by using bearing retainers in the column assembly.
For enclosed lineshaft, the bearings are also the tube
couplings of the shaft-enclosing tube. The shaft-enclosing
tube is stabilized in the column pipe by tube stabilizer.
Bowl Assembly
The bowls are generally of flanged construction for
accurate alignment and ease of assembly and disassembly.
Impellers may be either open or enclosed depending on
the design requirements. They are fastened to the pump
shaft by taperlocks. For temperatures over 140°F (60°C)
and in the larger size bowls (over 18”), impellers are
keyed to the shaft.
Installation
WELL CoNdITIoNS
When the DWT pump is to be installed in a well,
consideration must be given to the well before
installation. Check the inside diameter of the well and
the maximum outside diameter of the bowl and column
assemblies to determine that there is adequate clearance
to install the pump assembly in the well casing. Also
insure that the well is deep enough to receive the full
length of pump.
1. The DWT pump unit must be operated in a straight
portion of the well.
Installing a unit in a crooked well may
bind and distort the pump column with
potential resulting malfunction.
2. When the straightness of the well is not known,
the well should be “gauged” prior to installation
by lowering a dummy assembly, slightly longer and
larger diameter than the bowl assembly. Gauging is
also important when a stepped well casing is used,
with the lower part of the well casing having small
inside diameter.
3. The well should be developed with a test pump
prior to installing the permanent pump. Test
pumping the well serves several purposes. It
removes the excess sand encountered during the
initial pumping of the well. Pumping sand or other
abrasives with a DWT pump will shorten the life of
the pump and can void the warranty.
4. The test pumping also provides a means of
determining the capacity and drawdown. The well
capacity should equal or exceed the pump capacity.
If the pump removes water at a higher rate than
the well produces, the drawdown will be excessive
and the pump will cavitate or ‘starve’ resulting in
damage to the pump.
5. The pump must be equipped with enough column
pipe to assure that the bowl assembly remains
submerged during operation.
CAUTION