Teikoku USA | Chempump
Instruction Manual NC-Series 0220
5
1.1 General Design and Operation
The Chempump
TM
NC-Series is a combined centrifugal pump and
squirrel cage induction electric motor built together into a single
hermetically sealed unit. The pump impeller is a closed type, and
is mounted on one end of the rotor shaft which extends from the
motor section into the pump casing. The rotor is submerged in the
fluid being pumped and is "canned" to isolate the motor parts
from contact with the fluid. The stator winding is also "canned"
to isolate it from the fluid being pumped. Bearings are submerged
in system fluid and are continually lubricated.
Chempump
TM
pumps have only one moving part, a combined
rotor-impeller assembly which is driven by the magnetic field of
an induction motor. A portion of the pumped fluid is allowed to
recirculate through the rotor cavity to cool the motor and lubricate
the bearings. The stator windings are protected from contact with
the recirculating fluid by a corrosion resistant, non-magnetic,
alloy liner which completely seals or "cans" the stator winding.
The recirculating fluid passes through a self-cleaning cylindrical
filter (fitted in the discharge nozzle of the pump casing), through
the circulation tube, to the motor adapter, entering the motor
section at the front bearing. A portion of the pumpage flows
across the front bearing and returns to the rear of the impeller.
The remainder passes over the rotor, across the rear bearing, and
returns to suction through a hollow shaft. See
The Chempump
TM
sealless pump is a precision built unit that, with
proper care, will give years of trouble-free, leakproof service. This
manual, containing basic instructions for installation, operation
and maintenance of Chempump pumps, is designed to assist you
in obtaining this service.
It is important that the persons responsible for the installation,
operation and maintenance of the pump, read and understand
the manual thoroughly. Trouble-free performance begins with
proper pump selection and application. If the selected pump
does not have the required performance characteristics, or if the
materials of construction are not properly specified for the fluid
being handled, unsatisfactory operation may result. No amount
of maintenance can compensate for this.
If you are in doubt on your NC-Series selection or application,
write or call your pump engineering representative or the factory
for assistance and advice. Additional copies of this manual are
available from Teikoku field representative or from the factory.
1.2 Stator Assembly
The stator assembly consists of a set of three (3)-phase windings
connected in a one (1) circuit wye arrangement. Stator lamina-
tions are of low-silicon grade steel. Laminations and windings are
mounted inside the cylindrical stator band. End bells, welded to
the stator band, close off the ends of the stator assembly. Back
up sleeves are provided to strengthen those areas of the stator
liner not supported by the stator laminations. The stator liner is
a cylindrical "can" placed in the stator bore and welded to the
rear end bell and front end bell shroud to hermetically seal off the
windings from contact with the liquid being pumped. Terminal
leads from the windings are connected to a pressure tight termi-
nal plate isolating the stator cavity from the customer’s electrical
connections in the Teikoku supplied connection box.
1.3 Rotor Assembly
The rotor assembly is a squirrel cage induction rotor constructed
and machined for use in the pump. It consists of a machined
corrosion resistant shaft, laminated core with copper bars, end
rings, corrosion resistant end covers, corrosion resistant can and
an auxiliary impeller. The shaft is provided with an impeller key
arrangement at one end to receive the impeller and is threaded
at the same end to receive the inducer which retains the impeller.
The rotor end covers are welded to the shaft and also to the rotor
can which surrounds the outside of the rotor, thus hermetically
sealing off the rotor core from contact with the liquid being
pumped. An auxiliary impeller is mounted to the rear end cover
1. General Information
Figure 1-1. Reverse Circulation Type-R (Plan 13-SE)
