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4 Installation
Check
Check that the piping is installed as
straight as possible and that any
unnecessary bends are avoided. Where
necessary, use 45° or long-sweep 90°
fittings.
Check that all piping joints are leak
tight.
Check that the inside diameters of the
flanged joints match properly.
Check that burrs and sharp edges are
removed when you make up the joints.
When you anticipate considerable
temperature changes, check that
equipment for absorbing expansion is
installed in the system.
When you use an isolation pad, check
that flexible piping is used on both the
suction and discharge sides of the
pump.
Check that the pipeline has isolation
valves around the pump and a drain
valve in the suction pipe.
4.4.2 Suction piping checklist
The sizing and installation of the suction piping is extremely important. It must be selected
and installed so that pressure losses are minimized and sufficient liquid flows into the
pump when it is started and operated. Many NPSH problems can be directly attributed to
improper suction piping systems.
Piping checklist
Check
Keep the suction piping short in length, as
direct as possible, and never smaller in
diameter than the pump suction opening.
Check that the elbows in the suction piping
for horizontal double-suction pumps are
installed per the Hydraulics Institute
Standards since there is always an uneven
turbulent flow around an elbow.
Check that pipe reducers on the inlet side
have no more than one pipe diameter
reduction in a single reducer.
When operating on a suction lift, check that
the suction pipe slopes upward to the
pump nozzle.
(Optional) You can install a short section of
pipe adjacent to the suction flange such as
Dutchman or a spool piece that is designed
so that it can be readily dropped out of the
line.
28
Explanation/comment
This helps to decrease friction losses.
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This helps to avoid strain on the pump.
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Explanation/comment
If the suction pipe is short, the pipe diameter can be
the same size as the suction opening. If longer suction
piping is required, pipes should be one or two sizes
larger than the opening depending on piping length.
When there is an elbow in a position other than the
vertical when in relation to the pump suction nozzle,
this causes more liquid to enter one side of the
impeller than the other. The result is highly
unequalized thrust loads that overheat the bearings
and cause rapid wear, which adversely affects the
hydraulic performance. See the Example of
unbalanced loading figure.
This avoids excessive turbulence and noise.
A horizontal suction line must have a gradual rise to
the pump. Any high point in the pipe can become
filled with air and prevent proper operation of the
pump.
This facilitates the cleansing of the liquid passage of
the pump without dismantling the pump. With this
arrangement, anything that clogs the impeller is
accessible with the removal of the spool piece or pipe
section.
Checked
Checked
e-XC INSTRUCTION MANUAL
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