Chapter 74- Pump Operation And Maintenance

Question 1

Pump wear rings are installed on an impeller by set screws, threading or:

Answer 1

Shrinking

Question 2

Wear rings are usually constructed of:

Answer 2

Bronze or cast iron

Question 3

Wearing rings

1. Are used on impellers
2. Are used on the casing
3. Give protection to the shaft
4. Reduce the maintenance cost of the pump

Answer 3

1, 2, 4

Question 4

A component which is used to prevent leakage between the stationary pets of the pump and the hub of the rotating impeller

Answer 4

Wearing ring

Question 5

This component reduces the clearances of the rotating impeller and the stationary casing

Answer 5

Wearing ring

Question 6

When the clearances of the wearing rings increase it causes a decrease in ___________.

Answer 6

Efficiency

Question 7

The purpose of a shaft sealing on a pump is:

Answer 7

To stop fluids from leaking along the shaft of the pump

Question 8

The liquid to a lantern ring:

Answer 8

Keeps the air out of the pump

Question 9

A stuffing box

1. Stops air leaking into the casing when the pressure is below atmospheric
2. Decreases leakage out of the casing when the pressure is a novel atmospheric.
3. Is always supplied with a lantern ring
4. Is filled with packing

Answer 9

1,4

Question 10

Compressing type packing:

1. Prevents air entering the pump
2. Reduces the maintenance cost on pumps
3. Protects the shaft from scoring and corrosion
4. Is used on all mechanical seals

Answer 10

1, 2

Question 11

The seal cage on the shaft of a centrifugal pump

Answer 11

Distributes sealing water to the packing

Question 12

New pump packing should be installed:

Answer 12

Loose enough to allow leakage for lubrication

Question 13

If a stuffing box is to prevent the ingress of air, it is equipped with

Answer 13

Seal cage

Question 14

If the packing gland of a centrifugal water pump is leaking too much, you should:

Answer 14

Tighten up the gland but permit a slight amount of leakage

Question 15

Often graphite or grease are incorporated into the packing material as a lubricant, they are also called the___________.

Answer 15

Saturant

Question 16

Another name for compression type packing is

Answer 16

Jam type packing

Question 17

Mechanical sealing

Answer 17

Are used when leakage is objectionable and replace stuffing boxes

Question 18

The main advantage of a pump using a mechanical seal

Answer 18

Less maintenance

Question 19

The component of a mechanical seal, which prevent axial leakage is the

Answer 19

O-ring

Question 20

The main disadvantage of mechanical seals compared to packing and stuffing box methods are

Answer 20

Greater initial cost

Question 21

Factors that may affect the type of materials used in a mechanical seals mating ring depend on

Answer 21

Type of fluid, temperature, pressure, pump speed, sealing design

Question 22

Flexible couplings will compensate for

Answer 22

Axial shaft misalignment

Question 23

For coupling with hubs or flanges of the same diameter a ________ can be used to check for offset or axial misalignment

Answer 23

Straight edge and tapered feeler gauge

Question 24

A very accurate method of checking flanges for offset and axial misalignment which can be used on flanges is the

Answer 24

Dial indicator

Question 25

Proper priming and venting of a pump is important especially if

Answer 25

The pump has a stuffing box or a lantern ring

Question 26

To prime a centrifugal pump refers to

Answer 26

Filling the pump casing with liquid and removing the air

Question 27

Four advantages of a mechanical seal over a packing gland

Answer 27

• less maintenance
• no wear to shaft
• leakage is reduce to a min
• allow for high temperatures and pressures

Question 28

Pump wear rings are installed on an impeller by set screws threading or

Answer 28

Shrinking

Question 29

Wear rings are usually constructed of

Answer 29

Bronze and cast iron

Question 30

The seal cage on the shaft of a centrifugal pump

Answer 30

Distributes sealing water to the packing

Question 31

If a stuffing box is to prevent the ingress of air it is equipped with

Answer 31

A seal cage

Question 32

Any leakage occurring through the surfaces of a mechanical seal will

Answer 32

Be radial to the shaft

Question 33

The component of a mechanical seal which prevents axial leakages is

Answer 33

The ORing

Question 34

Shaft misalignment during operation of a pump can be caused by bearing wear, thermal expansion and

Answer 34

Shaft flexing

Question 35

Priming is

Answer 35

Filling the pump with water and removing the air

Question 36

If the pump speed is to high

Answer 36

The driver my be overloaded