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Final Review > Compressor, Blowers, Fans Review > Flashcards

Compressor, Blowers, Fans Review Flashcards

1
Q

3 Examples of Positive Displacement ROTARY Compressors;

A

Vane​
Liquid Ring (liquid piston)
Screw

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2
Q

What compressor will operate at the highest rpm?

A

Centrifugal

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3
Q

In a dynamic compressor the flow and the pressure attainable can be affected by:

A

-The smoothness of both the gas passages and the impeller​
-The clearances within the compressor​
-The speed of the impeller

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4
Q

Because of higher rotational speeds, ______, __________, and ___________ are areas of particular concern for dynamic compressor maintenance.

A

Seals, alignment, bearings

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5
Q

True or False;
In an axial compressor the air/gas passes radially along the compressor through alternate rows of stationary and rotating blades.

A

False

axially

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6
Q

True or False;
In an oil free screw compressor the female rotor is driven through a set of timing gears.

A

True

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7
Q

True or False;
In a vane compressor the air/gas is gradually compressed as the pockets get larger.

A

False

as the clearance gets smaller

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8
Q

Lobe Blowers produce __________ pressure, __________ flow(volume)

A

Low Pressure
High Flow(Volume)

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9
Q

True or False
Some rotary compressors can be used to create a vacuum by restricting the discharge.

A

false

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10
Q

Dynamic compressors convert velocity to pressure by:

A

Decreasing the gas velocity

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11
Q

Excessive discharge gas temperatures on a two stage dry screw compressor could be caused by:

A

Scaled up intercooler

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12
Q

In the case of centrifugal compressors, if the flow to discharge is low and a momentary reversal of flow occurs, the condition is called:

A

Surging

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13
Q

In both centrifugal and axial compressors when flow through the compressor becomes choked by either too high of a flow rate or speeds reaching sonic velocity, there is a condition called:

A

Stonewalling

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14
Q

The way the rotor’s radial position is set on large rotary vane compressors is by:

A

Shifting the bearing carriers and insert a dowel through the bearing carrier into the cylinder

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15
Q

There are three ways to arrange mechanical draft systems for boiler systems. What are they?

A

Induced, Forced, Balanced

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16
Q

What type of radial fan wheel is suitable for chunks of scrap material?

A

Open Wheel

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17
Q

Gas/air flow through a mechanical draft fan can be controlled by:

A

-Changing the fan blade angle​
-Using shutters at the inlet​
-Varying the speed of the fan

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18
Q

True or False;
Because liquid ring compressors deliver pulsation and oil free air, no separator is needed at the outlet.

A

False, needs to separate sealing fluid

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19
Q

When compared to a forced draft fan, an induced draft fan is usually:

A

Larger because it moves higher temperature gas

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20
Q

A vane compressor with excessive rotor slot wear would most likely:

A

Have increased vane wear and breakage

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21
Q

Sliding vane compressors do not need to be unloaded on a normal start-up because:

A

They use centrifugal force to move the vanes out and there is no seal to start compression until it is up to speed.

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22
Q

The balanced liquid ring compressor has:

A

A rotor that is centred in the casing

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23
Q

The method of capacity control that gives the most efficient unloaded operation of a rotary screw compressor is:

A

Geometry Control

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24
Q

The result of heating a gas in an enclosed space would be:

A

An increase in pressure

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25
Q

An example of a Dynamic compressor;

A

Axial

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26
Q

The radial journal bearing clearances in some centrifugal compressors can be changed by:

A

Shimming

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27
Q

If a liquid ring compressor was fed excess water for additional cooling, the most probable result would be:

A

A lower volume of gas would be discharged

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28
Q

What compressors used for oil free air, must have timing gears?

A

Dry Rotary Screw

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29
Q

Intercoolers can be located:

A

Between the 2nd stage and 3rd stage

intercoolers purpose - increase efficiency

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30
Q

An increased clearance volume in a rotary vane compressor:

A

Reduces the efficiency​

31
Q

If the minimum pressure valve on a sour gas service rotary screw compressor requires reseating, what safety precautions should be followed?

A

Lock and tag the prime mover​
Purge all lines​
Vent the compressor and lines

32
Q

Oil pressure alarms on a compressor are set to work when:

A

Oil Pressure falls below a predetermined level

33
Q

A pressure of one bar absolute is approximately equal to:

A

14.7 psia

34
Q

How is the lobe tip to casing clearance set in a large rotary lobe blower?

A

Adjust the bearing carrier location and dowel to set the location

35
Q

The seal oil pressure on a large dynamic compressor shaft seal must enter the seal at:

A

A pressure higher than the gas pressure it is trying to seal

36
Q

Axial flow compressors have ______ on both the rotor and casing

A

Blades

37
Q

The liquid ring compressor can be used to supply ____-_____ air:

A

oil-free

38
Q

True or False;
Cycloidal blowers trap the air by meshing action of the lobes and flutes and deliver the gas along the flute to the discharge port.

A

True

39
Q

True or False;
The natural draft system uses both forced draft and induced draft fans.

A

False;

no fans

40
Q

Within a lobe blower system, the pressure increase takes place:

A

In the discharge piping

41
Q

The correct order of installation for the following air line accessories is:

A

FRL
Filter, Regulator, Lubricator

42
Q

Blowers may be positive displacement or dynamic. The dynamic blower operates on the same principle as:

A

Centrifugal compressors

43
Q

What centrifugal compressor parts converts velocity to pressure?

A

Diffuser, Volute

44
Q

Pressure in a confined, static fluid acts equally and undiminished in all directions at right angles to the surface. This statement is known as:

A

Pascals Law

45
Q

Receivers must have what 3 components installed on them?

A

Pressure Gauge
Relief Valve
Moisture Drain

46
Q

A perfect vacuum is equal to:

A

-14.7 psig​

47
Q

To measure the deepest vacuum in a system, install the vacuum gauge:

A

Near the inlet port of the vacuum pump

48
Q

Capacity of a centrifugal compressor can be controlled by:

A

Controlling the flow of air to the inlet

49
Q

Centrifugal compressors produce_____ flow.

A

Radial

50
Q

Filters placed directly in the air line, after the receiver, are designed to trap:

A

Solid contaminants, oil and water vapour

51
Q

What is the advantage of using a two-stage compressor instead of a single-stage if both put out 100 CFM?

A

The two-stage would be more efficient

52
Q

For the same horsepower driver, what are the advantages of a screw compressor over a reciprocating compressor?

A

Higher volume​
More compact​
Less vibration

53
Q

An oil separator would be found on what type of compressor systems?

A

Rotary wet screw compressor

54
Q

The dewpoint of air or gas is:

A

The temperature at which the water vapour will condense

55
Q

When discharge gauge pressure reads 50 psig, how would you convert this reading to psia?

A

Add 14.7 psi to get psia reading

56
Q

Absolute zero is equal to:

A

-273 Celcius

57
Q

As a rule of thumb, the atmospheric pressure change for every 1,000 feet of altitude gain will cause on a column of mercury.

A

A drop of 1 inch

58
Q

What is necessary for air or gas to flow?

A

Create a Pressure Differential

high pressure will flow to low pressure

59
Q

The type of vibration isolation used on a fan depends primarily on:

A

The weight and vibration characteristics of the fan

60
Q

Vibration monitoring of large industrial, dynamic compressors is done by?

A

Continuously using proximity probes

61
Q

Large, single-suction, centrifugal fans are generally mounted using what bearings?

A

Double row spherical roller bearings

62
Q

Rotary screw compressors usually have thrust bearings on the:

A

Output end of both rotors

63
Q

When doing an installation on any compressor mounted with plain journal bearings, it is important to:

A

Avoid touching the bearing or journal surfaces with your bare fingers

oily finger skin is acidic

64
Q

What happens when the airflow through a compressor piping system is throttled from a six-inch line down to a three-inch line?

A

Velocity increases and pressure decreases

65
Q

When discharge gas is being recycled in a dynamic compressor, it goes through the aftercooler before reentering the compressor. What would occur if the aftercooler water jacket became scaled up?

A

The air temperature would increase

66
Q

How can axial forces be balanced on a multi-stage centrifugal compressor?

A

Balancing drums

67
Q

From a design standpoint, internal leakage (slip) in a dry screw compressor can be decreased most easily by:

A

Increasing the rpm

68
Q

The cold installed clearances between the rotors and the bearing carriers on a rotary screw compressor are usually held:

A

Tighter on the discharge end

69
Q

Discharge pressure at a screw compressor outlet port is not dependent on:

A

The speed of rotation

70
Q

The purpose of a minimum pressure valve in a sliding vane compressor is to:

A

Keep a minimum pressure for lubrication on start-up

71
Q

The most common maintenance on a dry sliding vane compressor is:

A

Replacing the vanes

72
Q

In a sliding vane compressor, which valve is opened by direct oil pressure from the sump?

A

Servo valve

73
Q

On oil flooded sliding vane compressors, what prevents pressure from leaking back from the compressor to the air inlet filter?

A

The non-return portion of the inlet throttle valve

74
Q

A rotary liquid ring compressor operating at sea level would have what pressure in the inlet cone?

A

Less than 14.7 psia

Final Review (5 decks)

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