Page 14 - Know and Understand Centrifugal Pumps

Prologue

Very few industrial pumps come out of service and go into the
maintenance shop because the volute casing or impeller split down the
middle, or because the shaft fractured into four pieces. The majority of
pumps go into the shop because the bearings or the mechanical seal
failed.
Most mechanics spend their time at work time greasing and changing
bearings, changing pump packing, and mechanical seals. The
mechanical engineers spend their time comparing the various claims of
the pump manufacturers, trying desperately to relate the theory learned
at the University with the reality of the industrial plant. Purchasing
agents have to make costly decisions with inadequate information at
their disposal. Process engineers and operators are charged with
maintaining and increasing production.
The focus of industrial plant maintenance has always been that the
design is correct, and that the operation of the pumps in the system is
as it should be. In this book, you will see that in the majority of
occasions, this is not true. Most of us in maintenance spend our
valuable time, just changing parts, and in the best of cases, performing
preventive maintenance, trying to diminish the time required to change
those parts.
We almost never stop to consider what is causing the continual failure
of this equipment. This book will help you to step away from the
fireman approach, of putting out fires and chasing emergencies.

This book is directed toward the understanding of industrial pumps and
their systems. It won’t be a guide on how to correctly design pumps,
nor how to rebuild and repair pumps. There are existing books and
courses directed toward those themes. By understanding the real
reasons for pump failure, analyzing those failures, and diagnosing pump
behavior through interpretation of pressure gauges, you can achieve