Dynamic Compressors

Front 1

What is the main purpose of a centrifugal compressor?

Back 1

To convert velocity and pressure

Front 2

A single stage centrifugal compressor has what type of casing?

Back 2

Volute

Front 3

How is a single stage Impeller attached?

Back 3

Directly to an extended motor shaft

Front 4

How does a single stage deliver air?

Back 4

In large amounts of low pressure air

Front 5

How do you increase the efficiency and capacity of a single stage compressor?

Back 5

With diffuser veins fit inside the hosing

Front 6

Increasing the speed of a single stage compressor increase as what?

Back 6

The volume

Front 7

How else can you increase the discharge pressures?

Back 7

By adding additional impellers to the rotor shaft

Front 8

Adding Impellers to the rotor shaft is known as what?

Back 8

Multi staging

Front 9

The compressor with multiple impellers is known as what?

Back 9

Multi stage compressor

Front 10

Where is the air intake of a Centrifugal compressor located?

Back 10

The eye of the impeller

Front 11

Where does air go as it discharges from the impeller?

Back 11

Into the diffuser or volute

Front 12

Velocity is transformed into what type of energy

Back 12

Pressure energy

Front 13

What happens to the pressure inside of a compressor as it passes through multiple stages?

Back 13

The pressure increases

Front 14

As velocity decreases pressure energy does what?

Back 14

Increases

Front 15

What are the two major moving parts of a centrifugal compressor?

Back 15

The rotor and impeller

Front 16

How is a horizontally split casing separated?

Back 16

Along the centreline of the housing or axially

Front 17

What is one major benefit of a horizontal split casing?

Back 17

The ability to remove the upper section and inspect the inside

Front 18

Were are vertically split or barrel casing be used?

Back 18

High pressure applications

Front 19

How is a vertically split casing split?

Back 19

Radially

Front 20

What is the Purpose of the impeller?

Back 20

Converts velocity and pressure

Front 21

What is done during assembly after each impeller has been fitted?

Back 21

The rotor shaft assembly is balanced

Front 22

What are the three types of impellers used?

Back 22

Open impellers, Semi closed impeller and closed impeller

Front 23

Where would you use an open impeller?

Back 23

Rough service environments

Front 24

We are closed impellers commonly used?

Back 24

The last stage of an axial compressor

Front 25

What is one benefit of a closed impeller?

Back 25

Higher pressure ratios And higher efficiency

Front 26

What is the purpose of a guide element?

Back 26

It controls and directs gas flow into the compressor

Front 27

What is the purpose of the inlet guide vanes?

Back 27

They control compressor out put an increase efficiency

Front 28

How is the outlet flow controlled?

Back 28

By throttling the inlet gas flow

Front 29

What is the purpose of a diaphragm

Back 29

Separates the impellers in the compressor casing

Front 30

What is the purpose of the Diaphragm?

Back 30

To change the direction and velocity of the gas stream

Front 31

What is the purpose of a diaphragm?

Back 31

Guide Air from the discharge of one impeller to the eye of the next impeller

Front 32

What is the purpose of a labyrinth seal in a diaphragm assembly

Back 32

Minimize leakage along the shaft

Front 33

Labyrinth seals are made of what type of material?

Back 33

Soft base metal

Front 34

Impellers generate thrust in which direction

Back 34

Direction of suction

Front 35

What is the purpose of a balance drum?

Back 35

Minimize axial thrust

Front 36

Where is the balance Drum located?

Back 36

At the discharge and behind the last impeller

Front 37

Where is the thrust bearing normally located?

Back 37

The suction end of the compressor

Front 38

Why are impellers generally arranged back to back?

Back 38

It creates a opposing flows which reduce axial trust

Front 39

What is the purpose of the double flow arrangement

Back 39

Doubles maximum flow capability and reduces discharge pressure

Front 40

Where are Labrinth seals generally located?

Back 40

In the diaphragm sections to prevent leakage from stage to stage

Front 41

What should be done when you encounter high pressures?

Back 41

Use interlocking Labrinth seals

Front 42

Why else are labyrinth seals used?

Back 42

To prevent noxious and poisonous gases from escaping to the atmosphere

Front 43

What material are labyrinth rings made of?

Back 43

Brass or stainless steel

Front 44

What factor Dictates the length of a labyrinth seal?

Back 44

The pressure drop required across seal. The higher the pressure drop the longer the seal

Front 45

Where is a carbon ring seal used

Back 45

Where there are low pressure differential’s

Front 46

Where were the carbon rings seal be located?

Back 46

Where the shaft emerges from the casing before going into the bearing housing

Front 47

What is one characteristic of Carbon rings?

Back 47

They are self lubricating

Front 48

When are mechanical seals used?

Back 48

When operating speeds are slow enough to permit their use

Front 49

What are the two types of bearings are used in a compressor?

Back 49

Anti-friction and plain journal bearing

Front 50

Where would you use a plain journal bearing?

Back 50

On larger multi stage compressors, for high-speed

Front 51

What is one characteristic of an axial flow compressor?

Back 51

It consists of several stages and moves large volumes

Front 52

The air in an axial flow compressor travels through what?

Back 52

Series rotating blades and stationary bands

Front 53

What occurs as gas moves through a set of rotors and stators?

Back 53

Gas pressure increases each time

Front 54

What occurs as gas enters the stater section and slows down?

Back 54

Pressure Increases

Front 55

What is the simplest and best method for controlling Compression?

Back 55

Varying the speed of the drive motor or use a variable position stator blades

Front 56

What are the two types of rotors in an axial compressor

Back 56

Drum or solid disc

Front 57

How are disc rotors attached to rotor shaft

Back 57

Fir tree, dovetail and Bulb type design

Front 58

Where are the stater blades mounted to?

Back 58

Casings walls

Front 59

What is the purpose of adjustable stator blades?

Back 59

They are adjusted to suit flow rates and conditions of the compressor

Front 60

How was the compression ratio Of an axial flow compressor increased?

Back 60

A centrifugal impeller is placed at the final stage

Front 61

How can you counter act axial a trust?

Back 61

Use thrust bearings, a balance drum or opposing gas flow’s

Front 62

What are the symptoms of blade fouling?

Back 62

Reduction in gas flow

Or change in operating characteristics