Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Mechanical Theory > Theory 4 > Flashcards

Theory 4 Flashcards

1
Q

describe the relationship between pressure and volume

A

as pressure increases, volume decreases or vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe the relationship between boiling point and pressure

A

As pressure decreases boiling point decreases or vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are 3 methods of heat transfer?

A
  • convection
    -conduction
    -radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how does heat travel?

A

hot —> cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is it called when the temperature of a material increases but the state doesn’t change?

A

sensible heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is it called when the temperature of a material stays the same but the state changes?

A

latent heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is superheating?

A

substances temperature goes above its boiling point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is sub cooling?

A

cooling substances below its boiling point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

name the examples of the on-board refrigeration plants

A
  • cold room
    -cool room dairy
    -fruit and veg store
    -galley ready use cupboard
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the temperature range of the cold room?

A

-18 —> -22 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the temperature range of the cool dairy room?

A

4 —>6 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the temperature range of the fruit and veg store?

A

4 —>6 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the temperature range of the galley ready to use cupboard?

A

5 —>7 degrees C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the 4 components of the refrigeration cycle?

A
  • compressor
  • condenser
  • thermal expansion valve (TEV)
  • evaporator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the compressor

A
  • cool gas enters the compressor
  • compresses the gas to form a high pressure, temperature gas
  • provides the motive force in the cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the condenser

A
  • high pressure hot gas is condensed into a high pressure liquid
  • sub-cooling is used to ensure all gas is converted to liquid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the thermal expansion valve (TEV)

A
  • slows the flow rate of the refrigerant
    -lowers the pressure and temperature
  • TEV senses the temperature of refrigerant leaving the evaporator to control the flow of the refrigerant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe the evaporator

A
  • evaporators the liquid to a gas
    -superheats the refrigerant so no liquid enters the compressor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does the HP cut out do?

A

shuts down the plant if the pressure gets to high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does the oil separator do?

A

separates the oil from the refrigerant and directs the oil back to the compressor sump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does the liquid receiver do?

A

store’s refrigerant for maintenance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the drier do?

A

removes any moisture from the refrigerant liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the sight glass indicator do?

A

green indicates, its dry
yellow indicates its wet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the 3 methods of defrosting?

A
  • natural defrosting
  • hot gas defrosting
  • electric heating coil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

how often do you defrost refrigeration plant using natdefrosting?

A

every 3-6 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how often do you defrost refrigeration plants using hot gas defrosting?

A

4x15 mins per day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how often do you defrost refrigeration plants using electrical heating coil?

A

1 hour per day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what gases does the motels protocol aim to phase out of production and use of ?

A
  • CFCs
    -HCTCs
    -halons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what gases does the Kyoto summit agreement aim to phase out production and use of?

A

-CO2
-HFCs
-PFCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are the methods of leak detection ?

A
  • infrared leak detection system
    -oil slicks
    -spectrolyne dye and UV
  • snoop
    -halogen leak detector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what oils are commonly used in RN refrigeration plants?

A
  • OM70
    -SUNISO 3GS
    -SW68
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what does Hydroscopic mean?

A

readily absorbs moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

why are open/damaged cans of oil to be discarded?

A

to avoid contamination with moisture from the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how can oil be added to the sump in refrigeration plants?

A
  • sump filter plug
    -hand pump
    -dosing pot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what does the chilled water plants provide cooling for?

A
  • weapons systems
    -radars
    -ships computer systems
  • air treatment unit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is the difference between the chiller system and refrigeration system?

A

has a chiller instead of the evaporator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is used to cool the condenser and motor?

A

sea water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are refrigerant vapours dangerous?

A

displace the oxygen in the compartment as refrigerants tend to be heavier than oxygen so will sink to lower ares of the compartments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what gas is produced when refrigerants come into contact with heat?

A

Phosgene gas
(mustard gas)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what gas is produced when fruit and veg start to degrade?

A

CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what procedures need to be carried out before entering the refrigeration compartment?

A
  • people are to be informed before entering the compartment
    -breathing apparatus available
    -high and low exhaust fans are running
  • no smoking anywhere in the compartment
  • ensure the infrared leak detection system is working correctly
  • personal trapped warring lights are in working order
    -ensure there is a sensory
    -ensure the internal door opening mechanism is working correctly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what do you do if you get refrigerant in your eyes?

A

flush with water and report to medbay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what do you do if you get refrigerant on the skin?

A

wash off immediately and report to medbay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what equipment and uses require ventilation?

A

-cooling of electronic equipment
-CBRN
-habitability
-main machinery space cooling
- galley ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what are the configurations of ventilation?

A

-fan supply and exhaust
-fan supply and natural exhaust
-natural supply and fan exhaust
-natural supply and natural exhaust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

where and why is fan supply and fan exhaust used?

A

removes large quantities of air and provide fresh air for personnel working in the compartments

machinery space, galley, laundry, bathrooms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

where and why is fan supply and natural exhaust used?

A

supply of fresh air is primary objective
store rooms and workshops

48
Q

where and why is natural supply and fan exhaust used?

A

removable of noxious gases and flammable vapours is primary objective
paint shops, inflam stores, sprit rooms

49
Q

where is is natural supply and natural exhaust used?

A

minor unoccupied compartments and lobbies

50
Q

name the common filters

A
  • lint filters
    -panel filters
    -dust filters
  • supply fliters
    -grease fliters
    -flameproof gauzes
51
Q

where are the special filters?

A

-galleys
-store rooms
-axillary machinery spaces
- magazines
-paint stores

52
Q

which compartments have fire flaps built into exhaust trunking?

A
  • galleys
    -main machinery spaces
    -magazines
53
Q

what are the requirements of a ventilation system in an STP space?

A
  • 15 air changes an hour
  • low level exhaust system
  • excess of exhaust capacity from that supply
54
Q

what are the percentages of air used in the ATU’s?

A

-33% fresh air
- 67% recirculated air

55
Q

what do AFUs consist of?

A
  • preparticulate filter –> paper filters that remove all course particles
  • particulate filter –> fibre glass that removes Bactria
  • gas filter –> charcoal removes all known chemical warfare
56
Q

how does Citadel work?

A
  • a whole ship chemical, biological and nuclear shelter
    -by closing the ship down to an increased gas tight state
  • increasing atmospheric pressure within the shipabove external pressures by using AFUs
57
Q

when are Citadel tests carried out?

A
  • annually
    -prior to DED (Docking extended duration)
    -During harbour acceptance trials (HATs)
    -During sea acceptance trials (SATS)
  • During FOST workup
58
Q

what pressure is needed for the citadel to be effective?

A

2”WG

59
Q

when does the air bleed valve lift?

A

when air pressure exceeds 1/2 “WG

60
Q

when are AFUs used?

A

CBRNDC State 1 condition alpha zulu

61
Q

when is the crash stop used?

A

when all fans needed to be stopped in case of an emergency e.g. fire/explosion

62
Q

where is the crash stop operated from?

A

SSC/HQ1

63
Q

when are the fans restarted?

A

when checked that they are clear of smoked and debris

64
Q

what is the definition of a fluid?

A
  • substance that will readily take the shape of its container
  • capable of transmitting power
    -liquid or gas
65
Q

what are the advantages of hydraulics?

A
  • reliable
    -simple, easy to understand
    -infinite speed range
  • easily reversed
    -ability to withstand overload
  • no sparks risk
    -high torque at low levels
  • 1/12 size of equivalent electric motor
66
Q

what are the disadvantages of hydraulics?

A
  • fire risk with mineral oil systems
    -noise
    -risk of contamination
    -less efficient (85-95%)
67
Q

what does denso steel working mastic give off when ignited?

A

toxic gas

68
Q

where is denso steel working mastic stored?

A

flammable store

69
Q

when is denso steel mastic used?

A

upper deck for hydraulic fittings

70
Q

what is in pipework sealing joints and what are they made of?

A

O-rings
made of flurocarbon elastomers

71
Q

what dose fluorocarbon elastomers give off when heated above 300 degrees C?

A

toxic gases including hydrogen fluoride

72
Q

what PPE is required when working with flurocarbon elastomers?

A
  • PVS gauntlets
    -rubber boots
    -PVC coveralls
    -full face visor
73
Q

what are the overall health and safety risks when working with hydraulics?

A
  • hydraulic fluid can cause skin irritation
  • change oil soaked clothes immediately
    -any skin irritation should be reported to medbay
    -always consult hazard data sheet
    -mineral oil is a fire hazard, leaks cleaned up immediately
    -flexi hoses in date for test
    -gauge glass valves to be shut when not in use
    -suitable precautions to be taken before welding or burning in the vicinity
74
Q

what are the 2 types of hydraulic fluid?

A
  • petroleum based
    -synthetic based
75
Q

which oils are used in hydraulic systems?

A
  • OM33
    -OX40
    -OX30
76
Q

what colour is OX30?

A

Red

77
Q

what colour is OM33?

A

Ornage/yellow

78
Q

What colour is OX40?

A

Green

79
Q

What are the requirements for hydraulic oil?

A
  • be incompressible, transmit power effectively
  • food lubrication properties
    -good sealing properties
    -give up heat readily
80
Q

what does demulsibility mean?

A

the ability of a fluid to separate out from water

81
Q

what are the most common types of oi contamination?

A
  • airborne particles and moisture
    -construction dirt
    -dirt in new fluid
    -dirt produced by wearing in new systems
  • dirt from human sources
82
Q

what methods are used to reduce contamination?

A
  • good system design
  • filtration and filter maintenance
  • operation of filter and clogging indicators
  • good working practices
    -guardian filter pack
    -caps should be fitted to open pipework
    -clean working area
83
Q

what components are in the anchor windless hydraulic system?

A

tankk
filters
relief valve
cooler
pressure gauges
valves
non return on discharge side
float switch
pump
control valve
actuator

84
Q

what type of pump is used in the hydraulic system?

A

positive displacement

85
Q

what types of positive displacement pumps are used?

A
  • external gear pump
    -internal gear pump
  • vane pump
    -lobe pump
    -single piston pump
    -multi piston pump
86
Q

what does the control valve do?

A

controls oil flow and direction

87
Q

what does an actuator do?

A

reverts hydraulic pressure into mechanical motion

88
Q

what is the purpose of the drain leg?

A

to return cooling oil and sealing oil from the actuator to the tank

89
Q

what is an acumulator?

A

a device in which potential energy is held and smooths out pulsations

90
Q

what are two types of accumulators?

A
  • bag
    -piston
91
Q

what are axial piston pumps used in?

A
  • stabiliser systems
    -CPP sytsems
  • steering systems
92
Q

what is fresh water used for?

A
  • laundry
    -galley
    -shower and sinks
    -water heaters
    -medical use
    -bridge window washers
    -fresh water hose reals
  • machinery cooling
  • gas turbine washing
93
Q

what is desalinated (made water)called?

A

permeate

94
Q

what is waste water after desalination called?

A

concentrate

95
Q

what does TDS stand for?

A

total dissolved solids

96
Q

what is the TDS of sea water?

A

34,000ppm

97
Q

what is the TDS of the permeate?

A

250-300ppm

98
Q

how much of the supplied sea water is ejected overboard?

A

80%

99
Q

what is the TDS of the ejected concentrate?

A

56,00ppm

100
Q

what does the bag filter, filter down to?

A

60 microns

101
Q

what does the cartridge filter, filter down to?

A

10 microns

102
Q

what pumps is used in the reverse osmosis plant?

A

HP
3 piston
positive displacement pump

103
Q

what pressure does the pump in the reserve osmosis plant operate at?

A

65 Bar

104
Q

what does the concentration valve do?

A
  • can be open or closed
    -forcing more or less water through the membranes
  • controls the TDS of the permeate
105
Q

what anti-scalent is used in fresh water systems?

A

hyperspere

106
Q

what are the chlorine levels in the fresh water tank maintained at?

A

0.2 ppm

107
Q

who authorises/ supervises any addition of chlorine to fresh water tanks?

A

section head

108
Q

when are chlorine levels tested?

A

daily and before embarkation

109
Q

what colour are fresh water hoses?

A

blue

110
Q

what needs to be done to fresh water hoses before they are used?

A

flush them

111
Q

what are the tests carried out on fresh water?

A
  • CHEMets test (chlorine)
    -visual
    -taste
112
Q

how often do you carry out CHEMets test?

A

daily and before embarkation

113
Q

how do you record the levels in the fresh water tank?

A

sounding tube
dip tape
conversion chart

114
Q

how do you get hot fresh water onboard ship?

A

calorifier

115
Q

what does the air eliminator do?

A

eliminates air and prevents water hammer

116
Q

when are fresh water levels checked?

A

hourly

117
Q

where are fresh water levels recorded?

A

SCC

Mechanical Theory (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions