refrigeration and ventilation Flashcards
what is a cold room
freezer
what is a cool room (1)
fridge
what happens to the boiling point of water if you in crease and decrease the pressure acting apon it (2)
when you increase the pressure water boils at a higher temperature
when you decrease the pressure water boils at a lower temp
describe and name the 3 ways of moving heat (3)
conduction- heat transferred by direct contact
convection- heat transferred by air
radiation- heat transferred by radiation
give examples of the 3 ways of moving heat (3)
conduction- touching a hot stove
convection- a radiator
radiation- the sun
what states to materials exist in (3)
liquid, solid, gas
what is sensible heat (1)
where the state if matter isn’t changing but heat is
what is latent heat (1)
change in state without change in temp
what is super heat (1)
any agree above 100 degrees
101 degrees = 1 degree of super heat
what temp is a cold room (1)
-18 to -22 degrees
what temp is a cool room (1)
4-6 degrees
what temp is a fruit and veg store (1)
4-6 degrees
what temp is a gally ready use cupboard (1)
5-7 degrees
what does a compressor do in the refrigerator cycle (2)
provides motive force
turns lp gas to hp gas
what does a condenser do in the refrigerator cycle (2)
uses salt water to cool the gas
turns the hp gas to hp liquid
what does a tev do in the refrigeration cycle (3)
thermal expansion valve
turns hp liquid into lp liquid
senses the temp of refrigerant leaving evaporater using a liquid line stop valve
what does a evaporator do in the refrigerator cycle (1)
turns lp liquid to lp gas
what is sub cooling
cooling down from a gas/vapor to a liquid
what do the colours mean in the sight glass indicator (2)
green- dry
yellow- moisture
explain natural defrosting (3)
turning everything off
de- store
do it every 3-6 months
explain hot gas defrosting (2)
passing a hp gass through coils
max 1 hour a day for 15 minute intervals
explain electric heating coils (2)
rod wrapped around coils
max 1 hour a day
what is the montreal protocol 1987 (1)
phase out the use of cfc gass
what causes ozone depletion (3)
cfc
hcfc
halons
what is kyoto summit (1)
limit and reduce green house gasses
what is infra red leak detection system irlds (2)
senses atmosphere at various points around machinary and system pipework
control point outside compartment
what are oil slicks (1)
white deck plates to show if any oil leakage
what is spectolyne dye and uv lamp (2)
dye added to oil
use of uv lamp to detect leaks
what is snoop (2)
soapy demineralised water
applied to suspect areas and leaks will show up as bubbles
what is a halogen leak detecor (3)
hand held device
detects refrigeration leaks electronically
extremely sensitive
what is om70 (1)
general purpose
what is suniso 3gs oil (2)
synthetic oil used in t23s and tboats
what is sw68 (1)
R134A refrigeraants
what does hydroscopic mean (1)
readily absorbs moisture
what are the 3 ways to add oil to a sump (3)
sump filler
hand pump
dosing pot
what are chilled water plants used for (4)
weapon systems
radars
ships computer system
air treatment units
what does chilled water leave and return from the plant at (2)
leaved at 4-6
returns at 13-20
what are the steps before entering a refrigeration plant (8)
tell someone where you are
breathing apperatus running
fans running
no smoking
irdls working
warning lights working
have a sentry
door mechanism working
what is fan supply and fan exhaust and where do you find it (5)
using a fan to ventilate a compartment blowing in and out
wcs
bathrooms
laundries
machinery spaces
what is fan supply and natural exhaust and where do you find it (3)
using a fan to blow in and letting it naturally disapate
store rooms
workshops
what is natural supply and fan exhaust and where do you find it (4)
nothing to blow air in but using a fan to bring it out
paint stores
spirit rooms
inflam stores
what is natural supply and natural exhaust (2)
using nothing to ventilate
minor occupied compartments and lobbies
what kind of filters do you get (6)
panel
supply
grease
lint
dust
flamproof gauzes
where requires speacial filters (5)
galleys
store rooms
auxiliary machinery spaces
magazines
paint stores
where are fire flaps found (3)
galleys
main machinery spaces
magazines
how many air changes to stps require
(1)
15 an hour
what do magazines require (1)
100% treated fresh air
in a basic ac cycle what percentage of air is drawn in and recirc (2)
33% drawn in
67% recirc
what are the types of air filtration units (3)
nbc no6 mk1
nbc no7 mk1
no3 mk1
in afu sections what are pre particulate filters (1)
paper filters
removes course particlulate
in afu sections what is a particulate filter (2)
fiber glass
removes bacteria
in afu sections what are gas filters (2)
removes all chemical warfare agents
active charcoal filtering
when do you do a citidel test (5)
annually
prior to DED
during HATS
during SATS
during FOST work up
how do you do a citidel test (5)
close all openings
open and start afu
restrict access
search fir leaks
record results in SEF and D171 part 2
what is a crash stop and where is it (2)
built into ventilation system to stop fans incase of emergency
in HQ1/SCC
before a restart what do you do (1)
check vents are clear
