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The Practical Pumping Handbook

as it provides a greater angular rigidity and is the better arrangement for
accepting tilting moments that may result from shaft misalignment
difficulties.

In the purchase of replacement bearing, it is extremely important to
ensure you receive exactly the same bearing as was selected for the
original pump design. For example, in the 'same' 7000 series of angular
contact bearing, there are still a number of optional series and preloads.
Other variables within the same size bearing would include cage style
and materials as well as the contact angle. While numerical suffixes can
be cross-referenced from one bearing manufacturer to another, the
alphabetical prefixes and suffixes are frequently different, and you may
finish up with a different bearing with unfortunate results.

7.4 Other types of bearing
7.4.1 Cylindrical roller bearings
This bearing style replaces the =~iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii~,
single row deep groove ball ...............................................................................
"':!iiiiiii
bearing as the radial bearing in
some pumps designed outside
North America. In this style, the
cylindrical roller bearing has a
series of cylindrical rollers between
the outer and inner races of the ~HiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiHiiii ................
.............................................................................
bearing. Although it is incapable
of handling any thrust loads, the Figure 7.12. Cylindrical roller bearing
friction is very low and it can
support large radial loads.

7.4.2 Journal bearings
The sleeve type journal bearing is capable of absorbing the radial loads
from the shaft, but is not capable of handling any thrust loading. Most
frequently used in larger pumps, the sleeve usually contains an internal
bearing surface which is most commonly made from a babbitt alloy
material. This material minimizes friction while, at the same time,
allows any foreign particles to embed themselves in the babbitt and
dramatically reduce the potential damage to the shaft.
Good lubrication is critical in obtaining a reasonable life span from
journal bearings. To assist in providing a consistent lubricating film
between the bearing and the shaft, grooved distribution channels are
cut into the bearing surface.

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