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S e c t i o n 3
H O W I T W O R K S — P U M P
FIGURE 1: PUMP LIQUID END
Fluid is moved by a centrifugal pump through the use of centrifugal
force. Fluid is taken into the center of the impeller through the inlet
connection. Most centrifugal pumps prefer a positive inlet pressure
to prevent cavitation (lack of enough positive inlet pressure to
prevent liquid vaporization). This fluid is then caught by the vanes
of the impeller as it spins. This rotation of the fluid mechanically
by the vanes "throws" the fluid to the outside of the impeller and
toward the discharge port of the liquid end of the pump. This
mechanical movement of the fluid creates the discharge pressure
of the pump. Variables like inlet fluid supply pressure, impeller
diameter, motor horsepower and closed face versus open face all
effect the flow and pressure of the pump. Each of these variables
can be manipulated to achieve a desired flow and/or pressure.
Max Impeller Diameter Chart
POWER
Model Size
Kw
TM4H
0.4
TM4K
0.75
TM6L
1.5
TM6M
2.2
TM6N
3.7
TM10N
3.7
FIGURE 2: PUMP MAGNETIC DRIVE
A magnetic drive pump uses a balanced magnetic field to create
the rotation of the fluid impeller. Unlike a traditional centrifugal
pump which has a direct drive connection between impeller and
motor, a mag-drive pump eliminates the direct drive mechanism
and replaces it with a magnetic field. An outer magnetic bell
housing is mounted on the end of the pump shaft. This outer bell
is aligned on the outside of the rear casing. The pump impeller
is connected to a smaller magnet assembly and rides on an
internal shaft and bushing assembly. (The liquid end parts are all
isolated within the fluid head of the pump without the need for a
mechanical seal.) The smaller magnet assembly is mounted within
the center of the magnetic field of the outer bell housing. Although
these two magnet assemblies are separated by a fluid barrier, the
magnetic fields are aligned. When the pump motor is started the
outer bell housing begins to rotate. As the outer bell rotates, the
rotating magnetic field effects the inner impeller magnet. As the
two magnets begin to turn together, the impeller begins turning
and displacing fluid.
Max Impellar Diameter (mm)
Hp
50HZ
1/2
102
1
125
2
142
3
156
5
165
5
145
4
60HZ
90
108
123
135
150
125
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