6
WARNING - Coupling guards must be used to
avoid serious injury to operating personnel.
5. GROUTING
Grouting compensates for unevenness in the foundation
and prevents vibration and shifting after mounting is
complete. Build a form around the base plate to contain
the grout, and sprinkle area with water to obtain a good
bond. The base should be completely fi lled with a good
quality, non-shrinking grout. The usual mixture for grouting
is one part Portland cement and two parts sand with
suffi cient water to fl ow freely. It is also desirable to grout
the leveling pieces, shims or wedges in place. Foundation
bolts should be fully tightened when grout has hardened,
usually about 48 hours after pouring.
6. PIPING
The pump suction and discharge connections are not
intended to indicate the required suction and discharge
pipe sizes. The pipe diameter must be selected according
to the requirements of the pumping system and
recommended friction losses for the liquid being pumped.
Usually, it is advisable to increase the size of both the
suction and discharge pipes at the pump nozzles to have
minimum acceptable friction loss, suction pipe should
never be smaller in diameter than the pump suction
nozzle. When suction pipe is of larger diameter than the
pump suction nozzle, an eccentric reducer is required to
eliminate possible air or vapor pockets at the pump suction
inlet.
Both suction and discharge pipes must be supported
independently near the pump, so that when piping is
connected to the pump, no strain will be transmitted to the
pump. Piping should be arranged with as few bends as
possible, and, preferably, with long radius elbow whenever
possible.
Where vibration noises must be kept to a minimum a
fl exible connection is recommended on both the suction
and discharge lines. This will eliminate any sound being
telegraphed through the pipe system.
NOTE:
Flexible connector should have limiting bolts to
contain hydraulic forces.
SUCTION PIPING
A horizontal suction line must have a gradual rise to the
pump. Any high point in the suction pipe can become fi lled
with air and prevent proper operation of the pump and may
cause loss of prime. The pipe and fi ttings must be free of
all air leaks.
Any valves or fi ttings should located at a distance equal
to 5 to 10 times the diameter of the suction pipe from the
pump suction nozzle. If an elbow must be installed at the
pump suction, it should be installed in a vertical position
to reduce unequal fl ow into the pump, which may cause
cavitation in the pump (See Figure 3).
There is always uneven fl ow in an elbow when it is
installed in any position other than a vertical position. This
unequal fl ow allows more water to enter one side of the
impeller than enters the other side causing a reduction
in capacity and effi ciency. This condition may also cause
cavitation which would be characterized by noisy operation
and shorter pump life.
An eccentric rather than straight reducer and gate vale
with stem horizontal rather than vertical should be installed
in suction piping. (See Figure 3).
NOTE:
A gate valve in the suction piping should not be
used as a throttling device, as this may cause the liquid to
overheat during operation.
DISCHARGE PIPING
A silent type check valve and a gate valve should be
installed in the discharge line. The check valve, placed
between the pump and the gate valve, is to protect the
pump against pressure surges and to prevent water
running back through the pump in case of failure of the
driver. The gate valve is used in priming, starting and when
shutting down the pump. This is especially important when
the pump is operated against a high static head.
if increasers are used on the discharge side increase the
size of discharge piping, they should be placed between
the check valve and pump.
7. WIRING
For electric motor drives, connect power supply to conform
with national and local codes. Line voltage and wire capacity
must match the ratings stamped on the motor nameplate.
8. ROTATION
Before starting the pump, check the required direction
of rotation of the pump. The proper direction is indicated
by a direction arrow on the pump casing. Separate the
coupling halves, then start motor to see that it rotates in
the direction required by the pump. If it does not, reverse
any two main leads of the 3-phase wiring to the motor.
The coupling halves can be reconnected and the pump
primed for starting.
C - OPERATION
1. PRIMING
Install pet cocks on top of casing as shown.
CAUTION:
Before starting the pump, the casing and
suction line must be fi lled with liquid. The pump must not
be run until it is completely fi lled with liquid, because of
danger of injuring some of the parts of the pump which
depend upon liquid for lubrication. Wearing rings will not
seize when the pump is fi lled with liquid but are very liable
to do so when the pump is run dry.
Priming By Suction Pressure
When operating with suction pressure (fl ooded suction),
priming may be accomplished by bleeding all the air out of the
pump by opening the petcock located at the top of the upper
casing or at the top seal gland.
Summary of Contents for Deming 5260 Series
Page 7: ...7 Figure 3 ...
Page 22: ...Notes ...
