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Flashcards in Dynamic pumps Deck (80)
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1

What is specific gravity?

It is the ratio of the density compared to cool water. SG of water is 1. Less than 1 is lighter than water and more than 1 is heavier than water.

2

What is the conversion of psi to kpa?

1 psi = 6.9 kpa

3

What is the formula to determine pressure?

Pressure=force / area

4

What is atmospheric pressure?

14.7 psia

5

How much pressure is lost with elevation gain?

Approx 1/2 psi per 1000 feet gain

6

What is head pressure?

It is the height, in feet, of a column of water that is one foot square at the base

7

What does water weigh?

62.4 lbs/cubic foot

8

How much pressure is on One cubic foot of headwater?

.433 psi

9

What is differential pressure?

It is the difference between the discharge pressure and the suction pressure

10

What is vapour pressure?

It is the pressure at which a liquid flashes into a vapour at a given temperature

11

When the Pressure increases what happens to the boiling point?

The boiling point also increases

12

What are some causes of turbulent flow

Bends, abrupt changes in cross-section, fittings in the pipe, velocity that is too high

13

In Bernoulli's principle, what are the two types of energy that make up total head?

Head pressure, velocity head

14

What is the difference between static head, and dynamic(or total) head

Static is the distance, and dynamic is the distance plus all the energy needed to move the fluid

15

What is net positive suction head?

It is a measure of head at the pump suction. It is commonly referred to as npsha or net positive suction head available

16

How is net positive section head required determined?

It is done by the pump manufacturers testing

17

The npsha should be at least how much more than npshr?

10% higher

18

What is another name for radial pumps?

Centrifugal pump

19

What creates the kinetic(speed,velocity) energy?

The impeller

20

Describe an axial pump

There is no change in the direction of flow. It is also known as a propellor pump. They produce low discharge head, but large volume of flow.

21

Describe a radial (centrifugal) pump.

Discharge is perpendicular to the intake, has reasonably high discharge head.

22

What is the only pump that has straight blades?

High speed peripheral pumps. They can reach 25,000 rpm and head capabilities of 12,000 feet

23

Where would you find a stripper?

They are in a regenerative turbine pump, Inbetween the suction and discharge ports

24

What is the most common centrifugal pump?

Single stage, end suction pump.

25

What is the benefit of the vertical single stage end suction pump?

It saves space because pump can be incorporated in the piping

26

What is benefit of a single stage double suction pump?

It has a single suction inlet that then splits to allow flow to both sides. The opposing forces on either side cancel each other out, so it limits axial thrust.

27

What pump handles the most amount of pressure?

Multi stage barrel pumps. Handles pressures up to 6500 psi and 20,000 gpm. It has a double casing

28

What are the three types of impellers?

Open, semi open, closed

29

What are the shaped lines running from the center outward on the back side of the impeller?

Pump out vanes

30

What is a drawback of the open impeller?

The vanes are weak and bend easily.