"Multiplicity ought not to be posited without necessity."
— Occam's Razor
Smoke or Substance?
Some Misconceptions About Desirable Construction Features of Centrifugal Pumps
By Igor Karassik
I have no reason to believe that the field of centrifugal pumps has any more of a monopoly on a whole series of myths about various concepts of construction details than any other technological discipline. Some of these myths arose through sincerely acquired misconceptions about what should provide a more economical or reliable construction; others originated instead from the desire of the marketing or advertising arm of a manufacturing enterprise to create an imaginary technological superiority for a new product line. What I decided to accomplish in this tutorial is to examine a few of the myths that pertain to centrifugal pump construction and to try to shed some light on their origins as well as on their validity. More specifically, I have chosen six different details of construction wherein major differences in concept have evolved over the years.
As said before, there are many circumstances when differences of opinion between pump designers have little effect on the reliability of the equipment or on the ultimate life between overhauls. Thus, the choice between different designs is not overly important and the user will be well served regardless of the decision he makes in selecting the pump that he will install and operate.
On the other hand, there are areas of design philosophy where the selection will have an important effect on customer satisfaction. The areas that I have chosen to discuss in this paper fall into this latter category. When the real roots of the differences in design philosophy are not based on fact, but rather on misconceptions and the desire to create a preference for a given product line, the user must try to analyze such claims from an informed point of view. I hope that this tutorial will help him or her to do so, to distinquish between fact and fiction — between smoke and substance.
"When the real roots of the differences in design philosophy are not based on fact, but rather on misconceptions and the desire to create a preference for a given product line, the user must try to analyze such claims from an informed point of view."
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