ABC Pumping Systems and Hydraulics 2

Question 1

According to the affinity laws, if pump speed is doubled, the power (brake horsepower) required changes by a factor of:

Accepted Answer

8

Answer

2

Answer

4

Answer

1.5

Question 2

What does the specific speed of a pump indicate?

Accepted Answer

The type of impeller design best suited for given flow and head conditions

Answer

The rpm at maximum power consumption

Answer

The minimum suction head required

Answer

The horsepower at shutoff head

Question 3

In a parallel pump configuration, what happens to total flow and head compared to a single pump?

Accepted Answer

Flow increases, head remains approximately the same

Answer

Flow doubles, head doubles

Answer

Head doubles, flow remains approximately the same

Answer

Both flow and head remain the same

Question 4

What instrument is used to measure the flow rate in a pressurized water main using pressure differential?

Accepted Answer

Venturi meter or Pitot tube

Answer

Ultrasonic flow meter

Answer

Rotameter

Answer

Weir box

Question 5

The volute casing of a centrifugal pump is designed to:

Accepted Answer

Convert velocity head to pressure head as water exits the impeller

Answer

Increase impeller rotation speed

Answer

Filter suspended solids from the water

Answer

Cool the pump motor

Question 6

Which of the following conditions would cause a centrifugal pump to operate at a lower-than-expected flow rate?

Accepted Answer

Air binding or air entrainment in the suction line

Answer

Lower than designed system friction losses

Answer

Larger than specified impeller diameter

Answer

Lower discharge static head

Question 7

The wire-to-water efficiency of a pumping system accounts for losses in which components?

Accepted Answer

The motor, mechanical drive, and pump hydraulic efficiency combined

Answer

Only the pump impeller

Answer

Only the motor windings

Answer

Pipe friction losses only