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Millwright Level 3 > Module K (160301) > Flashcards

Module K (160301) Flashcards

1
Q

__________________ involves the compression of gases to raise pressure, which is then put to work when the gas is allowed to expand in a controlled manner.

A

Pneumatics

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2
Q

Air receivers are pressure vessels and, as such, come under the applicable codes enforced under the __________________

A

Alberta Boiler and Pressure Vessels Act

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3
Q

What is the purpose of cyclone separators and dryers?

A

They dispose of moisture in pneumatic system lines to prevent problems

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4
Q

What are the three piping systems?

A
  1. Grid
  2. Decentralized
  3. Loop
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5
Q

Which is the simplest piping system?

A

Grid

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6
Q

Which piping system is also known as a dead end system?

A

Grid

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7
Q

The pros of a grid systems are that they are simple and cheap. What are the cons of this system?

A

Because there is only one flow path for the air, workstations at the end of the system may experience air starvation.

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8
Q

What is the downside of using oversized compoents?

A

Though oversized components increase efficiency, they cost more to install

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9
Q

The ________________ problem is alleviated by a line sloping towards a water leg and the drop taken off the top of the main line.

A

mositure

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10
Q

The FRL unit must be installed in the air line in the correct position to prevent ___________________

A

contamination damage

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11
Q

What is the correct order to install an FRL unit?

A
  1. The filter vto clean the air and protect downstream components (like regulator)
  2. The regulator to maintain a set system pressure
  3. The lubricator to add a mist of oil to the air stream
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12
Q

What happens when an FRL is installed backwards?

A

The oil from the lubricator would gum up the regulator and then the filter would remove any oil left in the air before it got to its point of use

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13
Q

The ____________ around the filter keeps the swirling air from affecting the operation of the filter

A

Shroud

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14
Q

The __________ below the filter prevents the contaminants and moisture from becoming airborne again

A

baffle

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15
Q

What would happen if the spring in a regulator broke?

A

the valve will shut off

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16
Q

A piece of white cardboard placed near the ________________ of the component should give a pale yellow indication of oil.

A

exhaust port

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17
Q

What does dripping oil from the exhaust port mean?

A

the lubricator needs to be adjusted

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18
Q

Which motors are used in equipment due to their low weight and compact size?

A

Vane motor

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19
Q

What are some examples of equipment which uses a vane motor?

A

impact guns, grinders, and drills

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20
Q

What is the most common flow control valve for smaller pneumatic actuators?

A

needle valve

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21
Q

What is the most common flow control valve for larger pneumatic sysmetms?

A

ball and globe valves

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22
Q

What is the difference between venting regulators and non-venting regulators?

A

Venting regulators also act as relief valves for the downstream section of the circuit to prevent any possibility of an increase in pressure in this section

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23
Q

How does pressure affect the amount of moisture in the air?

A

The increase in pressure tends to reduce the amount of moisture the air can carry.

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24
Q

How does an increase in temperature affect affect the amount of moisture in the air?

A

Increased temperature will lead to an increase in moisture in the air

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25
Q

The best way to determine a dryer’s condition is measurement of ______________

A

dew point

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26
Q

How can you measure a dryer’s dew point?

A

With a sensor called a dew point hygrometer

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27
Q

________________ is the only mechanical means of drying air that suppresses or lowers the dew point

A

over-compression

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28
Q

What is over-compression?

A

the mechanical means of drying air which can lower the dew point

29
Q

Centrifugal separators are sometimes called _______________ separators

A

cyclonic

30
Q

Where are centrifugal separators located?

A

downstream of compressor aftercoolers or wherever excess moisture needs to be removed

31
Q

_______________ is heat that is added or removed and cannot be sensed by a thermometer

A

latent heat

32
Q

What is a British Thermal Unit (BTU)?

A

The amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit.

33
Q

How many BTUs does it take to raise 1 pound of water by 1*F?

A

One BTU

34
Q

How many BTUs does it take to vaporize one pound of water?

A

970 BTU

35
Q

What is a calorie?

A

The heat energy required to raise 1 gram of water by 1*C at atmospheric pressure

36
Q

______________________ are the least expensive method of dew point reduction from both operational and maintance perspectives

A

refrigeration dryers

37
Q

What is bead-type modified silica gel?

A

similar to silica gel, but spherical in shape. This gel is very porous

38
Q

How is the correct dryer size chosen?

A

By ensuing dryers provide the correct velocities so that the air passing through the desiccant spends adequate time in contact with it to ensure proper moisture removal.

39
Q

What is the benefit of a system that measures the dew point of the air leaving the dryer?

A

Since it prevents switching to regeneration cycle until the air exiting is not in acceptable limits, there is:
1. reduced wear of moving parts in valves
2. increased desiccant life

40
Q

______________ dryers can achieve lower dew points than any other types of dryer

A

adsorption

41
Q

What is regeneration?

A

A term used for the process of removing the accumulation of moisture from the dryer bed

42
Q

What are some examples of mechanical dryers?

A
  • liquid separators
  • centrifugal separators
  • demister pads
  • over-compression
  • coalescing filters
43
Q

What is a mechanical dryer?

A

A device that uses a mechanical or physical means to cause moisture to fall out of the air stream such as barriers and filters.

44
Q

What is the difference between the packed bore design and the packed spool design?

A

Packed bore: the o-rings are fixed in grooves in the body through which the spool slides
Packed spool: the o-rings are fixed in the spool

45
Q

What is a FRL unit?

A

filter regulator lubricator unit

46
Q

fog lubricators serve best when the flow to the component is _________ and _______

A

straight and short

47
Q

mist lubricators serve best when the oil must be ____________________________

A

carried for long distances, so that the oil will not settle in the line

48
Q

To function correctly, many ________components require lubrication

A

pneumatic

49
Q

____________________ supply clean oil into the line to be carried to the components

A

air lubricators

50
Q

Where must the air lubricator be located?

A

downstream from any device that might be contaminated by lubricating oil (such as paint sprayers)

51
Q

A ______________ swirls the air around the filter bowl

A

deflector

52
Q

Air dryers can lower the dew point to as low as ________

A

-40C or -40F

53
Q

Deliquescent dryers contain ______________________.

A

chemical dessicants

54
Q

What happens to the chemical desiccants that absorb moisture in a deliquescent dryer?

A

they are consumed

55
Q

The safety valve is usually set _____% above the system’s maximum pressure.

A

5% to 10%

56
Q

What is the usual maximum working air pressure?

A

690 kPa (100psi)

57
Q

What is the purpose of a safety valve?

A

to release any excessive pressure due to the failure of the unloading valve or a pressure surge

58
Q

The air receiver is built to specific standards. Safe operation requires that the receiver is equipped with which four items for safety?

A
  1. Relief or safety valve
  2. Drain valve
  3. Fusible plug
  4. Air pressure gauge
59
Q

When do aftercoolers cool the air?

A

Heat exchangers cool the air after it leaves the compressor and before it enters the receiver.

60
Q

Which component can also act as an aftercooler?

A

a receiver

61
Q

Where is a water trap installed?

A

Wherever the compressed air is cooled and may fall below its dew point.

62
Q

The amount of air slip in all screw compressors can be reduced by increasing _____________________

A

the rpm of the rotors

63
Q

What is the maximum continuous vacuum rating of a rotary vane (multi-stage) vacuum pump?

A

29.5 “Hg

64
Q

Under atmospheric pressure at sea level, pressure gauges read ______

A

zero (0 psig)

65
Q

How can you calculate the psia value?

A

Add 14.7 to psig

66
Q

Absolute zero, the temperature where no molecular movement occurs is equal to ______C and ______F

A

-273C and -459F

67
Q

What is the pressure rating at absolute zero?

A

0 psia

68
Q

What is the pressure rating at sea level, under normal conditions of temperature?

A

14.7 psia

Millwright Level 3 (15 decks)

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