Flowserve APKD - Manual (Page 15)

APKD DOUBLE-CASE, DOUBLE-SUCTION USER INSTRUCTIONS 26999903 07-13
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3.3 Design of major parts
3.3.1 Drivers
Solid shaft drivers: where the rotor shaft is solid and
projects below the driver-mounting base. This type
driver requires an adjustable coupling for connecting to
the pump.
3.3.2
Discharge Head Assembly
(See also section 3.2.2.1)
The discharge head supports the driver and bowl
assembly as well as supplying a discharge connection
in most cases.
A shaft sealing arrangement is located in the
discharge head to seal the shaft at its exit from the
liquid chamber.
The shaft seal will usually be either a mechanical
seal assembly or stuffing box with an open lineshaft
or a tube-packing box with an enclosed lineshaft.
3.3.3 Column
assembly
The column assembly consists of column pipe, which
connects the bowl assembly to the discharge head
and carries the pumped fluid to the discharge head.
Houses and supports the shaft and may contain
bearings. Typical column assembly shown below:
a)
flanged column assembly
Figure 3.8
The column supports shaft assemblies, that are of an
open lineshaft construction utilizing the fluid being
pumped to lubricate the lineshaft bearings. The shafts
are key coupled with clamp ring design.
See sectional drawings supplied with the pump for
exact column assembly details as per the order. The
size and configuration vary depending upon the
specific order requirements and application criteria.
3.3.4 Bowl assemblies
The bowl assembly consists of impellers rigidly
mounted on the pump shaft coupled to an electric
motor. Impellers are cast wheels with multiple diffuser
vanes and are generally coated to meet the hydraulic
requirements. See section 8.0 for cross sectional and
part details.
3.3.5 Suction
strainers
Ina new installation, great care should be taken to
prevent dirt, scale and welding beads from entering
the pump, as it is particularly important to protect the
numerous close running fits form abrasive matter
present in new piping.
The suction system should be thoroughly flushed
before installation the suction and making up suction
piping to the pump
The suction strainer should be installed 4 pipe
diameters away from suction.
Cone Type Strainer
Figure 3.9
3.3.6 Impellers
The double suction first stage impeller (3A) is keyed
and held in position on pump end shaft (10A) by shaft
nut. The shaft nut is secured to the shaft with set
screws. The remaining single suction intermediate
impellers are also keyed. Each impeller is held in
position on the upper shaft by use of a split lock
collar secured with cap screws. All impellers are of
the enclosed type, one piece constructions, and are
dynamically balanced.
3.3.7 Stuffing
box
Some APKD’s are fitted with stuffing boxes. In such
cases, stuffing boxes are normally adequate for
working pressures up to 20.7 bar (300 psi). Refer to
stuffing box User Instructions for specifications.