"How to increase the efficiency of a centrifugal pump (monoblock) from manufacturing point of view"?

Answer 1

According to your question I am telling the way of increasing efficiency from manufacturing aspect only (not from considerations of hydraulic aspects).

Do you remember Moody's Diagram and the Darcy-Weisbach Relation for flow through pipes in Fluid Mechanics?

From Darcy-Weisbach equation frictional head loss is proportional to the friction factor 'f' (as the head develoved by the pump and discharge cannot be changed; also diameter nd length cannot be changed as it is considered in design part and not in the manufacturing section). So to decrease frictional head loss i.e. to increase efficiency, 'f' has to be reduced. Now, recall Moody's Diagram, for turbulent zone the friction factor depends on Relative Roughness.

Relative Roughness = (Average Roughness Height)/(Diameter)

Diameter is fixed from design considerations, so you have control over 'Ra'-value (Average Roughness Height) only. If the surface finish of the pipings are made better 'Ra'-value can be reduced. Thus efficiency will be increased.



To william l:
The diameter and length of tubings are fixed by the "Design Engineer" and not by the "Shop Floor Engineers". So a manufacturing section of a factory cannot increase or decrease the dimensions of the drawing at their will.

Answer 2

decrease the size of the tubing goin to the pump