refrigeration and hazards Flashcards
TEV?
thermal expansion valve
3 ways to make heat
convection: radiators etc
conduction: heat travelling from hot to cold
radiation: heat from the sun (sunburn)
two types of heat and what they are
sensible: state stays the same, but temperature is added
latent: state changes but temperature remains the same
where does subcooling stand in terms of temperature
90 degrees celsius
LP cut out
cuts off the compressor if pressure isn’t enough
HP cut out
cuts off compressor is there’s too much pressure
oil separator purpose
separates oil from the gas, and the oil is returned to the compressor
liquid receiver purpose
acts as a reservoir for liquid produced
drier and sight glass purpose
removes moisture from the refrigerant, on the glass dial it will indicate whether it’s good or bad by green or yellow
three ways to defrost
naturally, hot gas defost, and electrical heat coils
natural defrost
turn it off and let it defrost itself
hot gas defrost
performed for an hour (4 x 15mins) everyday
coils
coils are wrapped around the evaporator an hour before
montreal and kyoto protocols
phasing out CFC’s around the world
about greenhouse gases and the reduction of using them
ways to spot a leak
IRDLS infra-red leak detection system
oil slicks
spectrolyne dye and UV lamp
snoop (soapy water)
halogen leak detector
types of oil
OM70: general purpose refrigerant oil used with CFC machines
SUNISO: synthetic oil used on 23’s and T boats
SW68: synthetic used on R134a refrigerants
how oil can be added to refrigerant systems
sump filler plug
hand pump
dosing pot
what chilled water plants provide chilled water for?
weapons systems
radars
ships computer system
air treatment units ATU’s
chilled water temperature?
4-6 degrees celsius
refrigerant leak gas?
phosgene/mustard gas
precautions for going into the freezer?
check the safety lights, and handles
take a refrigerant gas monitor in with you beforehand
make sure exhaust fans are running
what’s the ventilation used for?
cooling of electric equioment
CBRN
habitability
main machinery space cooling
galley venitlation
what’s the ventilation used for?
cooling of electric equipment
CBRN
habitability
main machinery space cooling
galley ventilation
four basic combinations for supply and exhaust vents
fan supply and exhaust
fan supply and natural exhaust
natural supply and fan exhaust
natural supply and exhaust
types of filters and uses
panel filters: for vents susceptible to bad stuff
supply filters: ATU’s
grease filters: galleys
lint filters: laundry
dust filters: computers and sickbay
flameproof gauze: inflammable stores, hangers etc
vent systems identification numbers
first number: denotes which deck
second: denotes which section
third: position of the fans, odd for starboard and even for port
places which require special filters
galleys
store rooms
magazines
paint stores
auxiliary machinery spaces
special requirement vent places, and why
galley: due to increased risk of fire
aux machine space: subject to build up of fumes so 50% of vents are above deck
STP’s: requires 15 air changes an hour due to conditions
magazines: rooms with weapons aren’t vented normally, they’re fitted with 100% naturally treated air
citadel tests and when carried out
annually
prior to extended docking periods
during harbour acceptance trials
during sea acceptance trials
required during FOST
how a citadel test is conducted
close all openings on the citadel boundary and system on resirc’
open AFU’s
restrict access to and from the citadel
search for leaks and do temporary repairs
record the results on paper
crash stop ventilation
allows all vents to be stopped immediately during fires etc
