f) Flush each sub-system with a compatible, non-toxic, non-
hazardous, stable liquid. Drain into individual containers
for each fluid. Disconnect and remove all auxiliary piping.
g) Carefully bleed off any pressure remaining in the pump.
Pressure remaining in the pump will be dependent upon
the pressure in the system when the pump was stopped;
the quality, type, and condition of the isolation valves;
the thermal expansion values of the fluid and the pump
material; and the change in the vapor pressure of the
fluid between the temperature at the time the isolation
valves were closed and the ambient temperature.
Bleeding must be through a valved drain line from the
casing drain piped to a closed container mounted lower
than the pump. The container must be arranged with a
relief passage to some point where pressure and fumes
will not be harmful to personnel. The container must also
have a level device so that determination can be made
that sufficient fluid has been drained to empty the pump
cavity and the volume of fluid that was contained in the
run of suction and discharge pipe between the isolation
valves and the pump. After the initial rush of fluid from
the pump relieves the pressure, the drain valve can be
opened further to speed the draining operation. When
fluid quits running into the drain tank, gage the volume
to see if it is sufficient to have fully drained the contents
of the pump and the suction and discharge pipes
between the isolation valves. Now drain pumpage from
the containment shell drain connection in the same man-
ner as above for the casing drain.
If the system was constructed without any drain connec-
tions, it will be necessary to consult the designers of the
system for safe draining procedures.
h) Now drain any small piping, that contains the fluid
pumped, from all low points into the same container
used to drain the pump. Do not drain any other fluids
(different then the pumpage) into this container as they
may not be compatible. Personal injury, death, and/or
equipment damage could occur. Remove the frame drain
plug which will drain any fluid that may have leaked
into the frame. Drain and remove any auxiliary piping.
Remove the 1/4” NPT plug from the secondary contain-
ment seal drain connection in the bottom of the frame
(26). Drain the oil and/or any residual pumpage from a
possible leak of the primary pressure containment.
Remove the frame foot mounting bolts.
WARNING: Even though it might appear that the cavity being
drained has completely drained, be extremely careful about
opening the system and/or opening the pump. If something
solid in the pumpage moves to the vicinity of the drain connec-
tion, it could seal-off the drain and maintain pressure in the
cavity thought to have been drained. It is also possible that the
isolation valves are not sealing and therefore allowing liquid to
flow from the system into the pump. Personal injury, death
and/or equipment damage may occur if great caution is not
exercised.
i) Because of the above possibility, when you loosen the
gasketed joint at the back of the casing (5), loosen the
casing bolts (5D) only one full turn, and then use jack
screws in the flange of the casing cover (22) to break the
gasket seal. If fluid and/or pressure remains in the pump
it will spray out now. Use extreme caution, wearing
protective gear, to avoid injury. Do not proceed with
disassembly until leakage ceases completely. If leakage
does not cease, the isolation valves may not be sealing.
Note that if the pump was purchased without a drain, the
pump will contain fluid which will flow out at the time the
bolts are loosened and the gasket seal is broken.
WARNING: When you open the pump, the fluid will be exposed
to the atmosphere and personnel in the area. For the safety of
all involved, the risk of exposure can be reduced by flushing the
cavity that was just drained with a compatible, non-toxic, non-
hazardous, stable liquid, before disassembling the pump.
j) Remove the casing bolts (5D) and using a mechanical lifting
apparatus to support the weight, pull the frame assembly
from the casing (5).
In some instances, it may be necessary to remove the
coupling hubs from the drive shaft and the motor shaft to
allow the removal of the frame assembly.
k) Flush the wetted parts, now exposed, with a compatible,
non-toxic, non-hazardous, stable liquid.
l) Remove the gasket from the face of the casing (5) or the
casing back cover (22) dependent on which one the gasket
may have adhered to. The type of gasket and material of
construction will vary with service requirement. Attack by
prying and then, if necessary, layering off the old gasket
with a sharp scraper, attempting to remove it in the
largest possible pieces. Take care to not scratch the metal
surfaces. Wear heavy leather, long sleeve work gloves
when using the scraper. Wet the gasket before and during
the scraping operation to reduce the possibility of fibers
becoming airborne. Wear a respirator during this operation
and until all debris has been disposed of in a plastic
bag. Remove all of the gasket material down to clean
metal surfaces on both parts that contacted the gasket.
Place all of the gasket residue in a plastic bag, seal the
bag and dispose.
m) Remove the casing ring assembly (190) by prying it out
of the casing (5). Remove only if it needs to be replaced.
The inner component is made of carbon and will most
likely be broken during removal. CAUTION: Wear face
shield, gloves and a long sleeved shirt during this
disassembly as the carbon ring is under compression
and may fly apart.
n) The frame assembly of the pump can now be moved to
a more convenient location for further disassembly. Use
mechanical lifting equipment to move assemblies and
components.
DISASSEMBLY OF THE “FRAME ASSEMBLY”
WARNING:
Use only high quality tools.
Flush parts as disassembled to remove hazardous residue from
the pumpage and/or sub-system fluids.
Wear protective equipment as advised at the beginning of this
section.
PUMP FOUNDATION
The pump foundation provides rigid support to the baseplate
and maintains the alignment of the pumping unit. Baseplates
are designed to rigidly support the pump and driver without
vibration or distortion only when they are properly set, leveled
and secured to the foundation.
The purchaser may elect to mount the pump without grouting
the baseplate. In any case, the baseplate must be fully support-
ed by the customer's mounting means to prevent vibration and
distortion.
SUCTION AND DISCHARGE PIPING
Suction and discharge nozzle sizes of Dean pumps are select-
ed for proper performance of the pumping unit and are not
intended to determine the sizes of the suction and discharge
pipes. Pipe sizes must be determined by the user based on the
system requirements.
Suction piping should have a minimum friction loss and thus
should be as short and straight as possible with a pipe diameter
as large as economically feasible for the flow rate handled.
The suction pipe should be straight, for a minimum of eight
pipe diameters, into the pump. Suction piping should never be
smaller in diameter than the suction nozzle size. When the suction
piping is larger than the suction nozzle size, an eccentric
reducer is required at the suction flange and must be installed
with the taper located on the underside to eliminate air or
vapor pockets.
Discharge piping may be the same size as, larger, or smaller
than the discharge nozzle as the system flow may demand.
In new installations or rebuilt systems, dirt, pipe scale, welding
slag and general construction debris may get into the piping. It
is important to prevent this material from entering the pump
and damaging pump parts. Bearings and magnets are espe-
cially subject to damage even by very small particles. To pre-
vent damage, a strainer or filter installed in the suction line is
recommended. Commercially available strainers or filters as
recommended by their manufacturers can do an excellent job.
Another form may be a cone strainer of 100 mesh installed in
a pipe cross placed with the cross in a vertical position and uti-
lizing blank flanges to cover the openings. In this set-up, the
top flange may be opened for inspection and the bottom flange
opened for cleanout. Ferrous particles in the pump system will
be attracted by the magnetic coupling and can cause rapid
wear of the containment shell. A magnet installed in the suction
strainer will attract the smaller ferrous particles which could
pass through the suction strainer. The magnet must be of a
material which can tolerate the corrosive effects of the liquid
and the temperature. In addition, special filtering and flushing
guards may be required. Consult your Dean representative.
Suction line screens or strainers may usually be removed when,
after several days of use, no dirt has been collected and the
system is clean.
Remember that screens and filters in the suction line are restrict-
ing devices which reduce the net positive suction head (NPSH)
available to the pump and should be considered at the time the
system is designed.
Whenever a filtering device is used, some operating procedure
must be established, to assure that restriction of liquid flow, to
the pump does not occur. As the filter traps debris, flow
becomes more and more restricted. The rate of plugging is
dependent upon the free area of the filter selected, and the
amount of debris in the system. Do not allow debris to accumu-
late to the point where the NPSH available to the pump is as
low as the NPSH required by the pump.
If the suction and discharge lines are insulated, be sure that no
insulation is placed on the pump except at the casing. It is
especially important that no insulation be placed on any air
cooling surfaces of the pump or its auxiliary piping.
INSTALLATION
T
YPICAL
F
OUNDATION
L
AYOUT
T
YPICAL
P
UMP
P
IPING
8
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