KSB GIW LCC 100-400, Руководство по обслуживанию

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LCC
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For expeller applications, the stuffing box used must be of
the ‘KE’ (low flow) type with a ring of packing between the
lantern ring and pumped fluid. All rings of packing should
be well coated with water resistant grease during
assembly.
7.6 Spare Parts Stock
Due to the erosive action of the slurry, many of the wet
end components of the pump may require replacement
during normal maintenance. Inspection or overhaul of the
mechanical components may also warrant replacement of
certain parts.
The following are recommended lists of parts to have on
hand for normal maintenance and inspection. The
quantities of parts kept in store will depend upon the
severity of the slurry duty and the number of units
operating. Maintenance practices may also favor keeping
fully built sub-assemblies or complete pumps on hand in
some cases. Previous experience in similar duties often
provides the best experience. If in doubt, contact your
GIW / KSB representative for specific recommendations.
Wet End Stuffing Box
• Casing (or casing liners) • Shaft Sleeve
• Impeller • Seal Water Ring
• Side Liner • Packing
• Gasket Kit • Gasket Kit
Bearing Assembly Expeller
• Bearings • Casing
• Gasket Kit • Plate
• Expeller
• Gasket Kit
7.6.1 Maintenance Procedures for Maximum Parts Life
The wear of slurry pump parts is influenced by many
factors and the following procedures are designed to help
you get the most out of your wet end wear parts. If
problems occur, contact your GIW / KSB representative
for a review of your application.
Also see section 7.7: “Operational Problems and
Solutions”.
Suction Liner
The suction liner should be rotated 180° at approximately
half-life if localized wear occurs. If localized wear is
severe, repair as recommended by GIW / KSB before
rotation.
A new gasket should always be used with a new suction
liner or new shell.
Impeller
The impeller to suction liner clearance should be adjusted
forward several times during its life cycle for maximum
impeller and suction liner life. See section 7.5.13.
In general, an impeller does not require replacement until
it fails to produce sufficient head for the application.
Impellers are sometimes changed too soon based on
appearance. Vibration caused by an impeller wearing out
of balance is rare but possible. If this occurs, the impeller
may be statically balanced by hand grinding on back
shroud.
The impeller should never be repaired by welding.
Shell
If wear is localized with a deep gouge, repair or replace as
recommended by GIW / KSB. Excessive wear problems
are usually indications that the pump is not operating at
the flow and head conditions originally specified for the
design.
7.7 Operational Problems and Solutions
Many pump wear problems are caused by unstable
system operation, or off duty pump operation. Although
the dynamics of slurry piping systems cannot be fully
addressed in this manual, the following items should be
considered. Also refer to section 8: “Trouble Shooting”
Sump Design
A minimum sump capacity of one minute at the expected
flow conditions should be provided. Sump design should
prevent any uneven flow of the solids to the suction. Often,
a flat bottom sump is best since it will allow the solids to
assume a natural slope of repose. The sump should be
observed during operation to insure that solids are not
building up and sloughing off.
Sump design should prevent the formation of a vortex, or
other means of introducing air into the pump. Where a
submerged suction is available, the depth of water level
above the pump suction is more important than the cross-
sectional area of the sump. Frothing of the sump should
be eliminated by the installation of baffles, a submerged
inlet pipe or other methods to prevent air becoming
entrained in the slurry. If unavoidable, frothing must be
accounted for in the system design and operation.
If the sump runs dry, the system will surge causing
accelerated pump wear. Pump speed or impeller diameter
should be decreased or make up water increased. If the
flow variations are too great, a variable speed motor may
be required.
Cavitation / NPSH Performance
The NPSH available must always be greater than the
NPSH required by the pump or cavitation will occur
resulting in head loss (drop in discharge pressure),
increased wear rate of the pump parts, and shock loading
of the pump bearing assembly. If any conditions occur,
consult your GIW / KSB representative for the NPSH
requirements of your pump.
To maximize the NPSH available to the pump, insure that
the suction line is as short and straight as possible and the
sump level is as high as possible, (or the suction lift as
small as possible in the case of a pump located above the
water level). Minimizing the number of valves or short
radius fittings and attaching a suction inlet bell will also
reduce entrance losses. A larger diameter suction pipe
may help, but one must be careful not to reduce the flow
velocity below safe carrying levels or bedding of the slurry
will occur and result in increased suction liner and impeller
wear.
In dredging applications where a free suction pipe or
suction cutter head is lowered into the solids to be
pumped, it is useful to have pressure gauges attached to
the pump suction and discharge. An operator, by