5.4 Scope of delivery
Pump can be delivered,
•
as a complete pump set including electrical motor,
base plate, coupling and coupling guard;
•
either without motor or
•
as bare shaft pump without base plate.
5.5 Accessories
•
Companion Flange
•
Foundation bolts
•
Shims
6 Description and function
6.1 Description of the product
Split casing pumps are either single or two stages. They
are of relatively simple construction, the casing being split
along the pump axis so that normal maintenance work can
be carried out without disturbing the position of either the
pumping set or pipe work.
6.1.1 Casing
The pump casing is of volute form, cast in halves, which
are bolted together along the pump axis. Gasket paper is
provided between the split flanges of top and bottom
casing. For accurate location casing halves, bearing
housings / brackets etc. are located with dowel pins.
The suction and delivery branches of the pump are cast
integral with bottom half casing, which also incorporate
the mounting feet. Holes are tapped on suction and
delivery branches for connecting the pressure gauges and
providing casing drain. Bores of bottom half casing are
grooved to provide location for stuffing box bushes. The
top half casing carries connections for liquid seal for both
sides. Air vent cock is fitted on the top and also priming
hole is also provided on the top of casing.
6.1.2 Neck ring
To prevent the entry of pump liquid from delivery side of
impeller to suction side, neck ring is provided. Fine running
clearance is provided between neck ring and impeller
neck. Periodic restoration of this clearance is necessary for
satisfactory performance of the pump (Table-6 pg. 14).
For two stage pumps these neckrings are located in the
bottom half of the casing by half spigot (tung and groove)
and its rotation is restricted by flat face of the top casing.
For rest of the single stage pumps plain neck rings with
neck ring pins in bottom casing for locking are used. The
neck ring pin is press fitted in the neck ring.
6.1.3 Sealing system
To prevent leakage along the shaft at the point of
emergence from the pump casing, gland packing, or
mechanical seals may be fitted in the stuffing box situated
at each end of the casing.
Gland Pack
For SCP pumps plaited cotton impregnated with oil and
colloidal graphite is used.
Mechanical Seal
SCP pumps are supplied with mechanical seals from all
leading manufacturers in India.
6.1.4 Rotating element
The rotating element of SCP pump consist of following
parts. It consists of a shaft on to which an impeller is placed
and arrested at its position with a key to avoid free rotation
with respective of rotation of the shaft. Renewable shaft
sleeves are provided on both sides to protect the shaft from
corrosion and erosion. The impeller is locked at its position
by sleeve and cowl nuts, which have threads left/right-
handed as per the direction of rotation of shaft.
The pump rotor is supported on deep groove ball bearings
on either side of the shaft. Bearings are located in the
bearing housing, which are attached to the end of the pump
casing. Stuffing box bushes are provided on either side of
the shaft on the sleeve and is located in the bottom half of
the casing in half-spigot. The purpose of stuffing box bush
is to guide the liquid toward the impeller eye. Whereas the
back face of the stuffing box provides support to gland
packing. Water thrower is placed after gland plate on both
side of shaft.
Installation and operating instructions WILO-Split Case Pumps
12