General information about electrical and centrifugal
pumps The diameter of the discharge opening of a centrifugal pump
determines its nominal size only and does not definitely fix its
rate of flow. It is recommended that the required rate of flow be
specified. Duplicate performance pump A duplicate pump is one in
which the performance characteristics are the same as another within
the variations permitted by these standards, and parts are of the
same type; but, by reason of improved design and/or materials, mounting
dimensions and parts are not necessarily interchangeable. Dimensionally
interchangeable pump An interchangeable pump is one in which the
mounting dimensions are such that the replacement pump can be mounted
on the existing bedplate and match existing piping and driver, with
hydraulic characteristics and materials to be specified. Interchangeability
may involve some variation, not necessarily significant, as a result
of manufacturing tolerances. Identical performance and dimensional
pump An identical pump is a duplicate of, and in addition is interchangeable
with, a specific pump. Where it is intended that a pump is to be
identical in all respects including parts, mountings, connecting
flange dimensions and materials, it should be identified as "identical
with Pump No. ____", not "duplicate."
Horizontal standardized pumps SNK
Horizontal single-stage centrifugal pumps, with axial suction
and radial delivery. The SKD pumps have dimensions and nominal
performances according to EN 733 (UNI 7467).
These can be connected to a two or four poles electric motor
with a coupling and mounted on a pressed metal bedplate according
to UNI EN 23661.
Cast iron spiral pump body and motor support, flanges according
to UNI 2236 PN10. Cast iron impeller, encased and dynamically
balanced with compensation of the axial thrust by means of
balancing holes.
Assembly of pump-motor through a coupling on a base-plate
enable an easy disassemblying of the complete rotor without
modifying the alignment of the group and without disconnecting
pipes and motor.
Use
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Performances
Multistage, axially split, single or double suction centrifugal pumps
Bare rotor
A bare rotor shall consist of the following as an assembly (where used):
-- a shaft with all nuts;
-- keys;
-- impellers;
-- impeller rings;
-- shaft sleeves;
-- interstage sleeve(s);
-- balancing drum and/or disc.
It shall not include such items as mechanical seal(s), gland(s), lantern ring(s), packing, deflector(s), oil thrower(s), oil rings(s), bearings, bearing appurtenances, coupling, pulley or sheave. A bare rotor may have to be disassembled for installation in the pump.
Rotating assembly
A rotating assembly shall consist of a bare rotor plus the following (where used): casing ring(s), interstage diaphragm(s) and bushing(s), diffuser(s), balancing ring or bushing, bearings and all other stationary or rotating parts required to be assembled over the shaft.
A rotating assembly shall include the following (where used):
-- packing or mechanical seal and gland(s);
-- deflector(s);
-- oil thrower(s);
-- oil ring(s);
-- bearing cover(s).
It shall not include coupling, pulley, or sheave, nor shall it include bearing housings except when these are of a design that requires they be assembled prior to mounting of the bearings.
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