Page 79 - Know and Understand Centrifugal Pumps

Know and Understand Centrifugal Pumps

Magnetic drive pumps
~ ~ ~~~ ~~ ~
BEARINGS LUBRICATED
WITH PROCESS FLUID

Figure 6-11 ~ ~ _ _ _
~~
This type of pump utilizes a conventional electric motor that drives a set
of magnets that drive other magnets fixed to the pump shaft. A non-
magnetic housing that isolates the pumped liquid from the
environment separates the rotating magnet sets. The impeller, the
driven magnet set, shaft and bearing assembly all operate inside the
pumped liquid. There are two types of magnet drives:

rn Eddy Current electromagnets that can experience some slip inside
the pump and may decouple.
rn Rare earth permanent magnets with no slip and not subject to
decoupling .

The advantages
rn No mechanical seal.
rn Considered leak proof (although some models use gaskets and o-
rings as secondary seals).
rn No product loss.
rn No exposure (neither liquid nor gaseous) to workers or the
environment.