Question

Cconsider the following statements:

1. Pumps used in series are generally of the centrifugal type.

2. Centrifugal pumps, though yielding comparatively smaller discharges than axial flow pumps, yield higher heads (at each stage) compared to axial flow pumps.

Which of the above statements is/are correct?
1. 1 only 
2. 2 only 
3. Both 1 and 2 
4. Neither 1 nor 2 

Answer 1

Correct Answer - Option 3 : Both 1 and 2 

Statement I – True

The basic difference between pump in series and in parallel is given below:

Pumps in Series	Pumps in Parallel
Discharge will remain same.	Discharge will be sum of the discharges in individual pump.
Total head = Sum of heads of all the pumps connected in series.	Heads against pumps are working remains same.
Ex: Pumps which has high flow rate are used in series such as Centrifugal pumps.	Ex: Pumps which has low flow rate are used in parallel so that their discharge can be increased such as Reciprocating pumps.

 

Statement II – True

Discharge order: Reciprocating pumps < Centrifugal pumps < Axial Flow pumps

Working Head order: Axial flow pumps < Reciprocating pumps < Centrifugal pumps