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25 Cards in this Set

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what year were high speed (1,750) reciprocrating compressors first installed on navy ships?
1950
what kind of parts to reciprocating compressors use?
commercial parts
what year were high speed (1,750) reciprocrating compressors first installed on navy ships?
1950
what is pumping down?
removing refrigerant from the part of the system to be opened prior to being opened to the environment
what kind of parts to reciprocating compressors use?
commercial parts
when PUMPING DOWN, where is the refrigerant confined?
refrigerant is confined to the recieveer by closing the liquid-lin stop valve and operating the machine. all gas is drawn back to the compressor and condensed in the condenser but is prevented from going farther by the liquid stop valve
what is pumping down?
removing refrigerant from the part of the system to be opened prior to being opened to the environment
what is BACKSEATING A VALVE?
turning the VALVE STEM all the way to the right (forward) closes the valve outlet. in this position, the gauge connection is open to the pressure in the compressor. turning the valve all the way TO THE LEFT (out), backseats the valve and closes off the gauge connnection. backseating prevents the escape of refrigerant from the gauge tap
when PUMPING DOWN, where is the refrigerant confined?
refrigerant is confined to the recieveer by closing the liquid-lin stop valve and operating the machine. all gas is drawn back to the compressor and condensed in the condenser but is prevented from going farther by the liquid stop valve
what is BACKSEATING A VALVE?
turning the VALVE STEM all the way to the right (forward) closes the valve outlet. in this position, the gauge connection is open to the pressure in the compressor. turning the valve all the way TO THE LEFT (out), backseats the valve and closes off the gauge connnection. backseating prevents the escape of refrigerant from the gauge tap
what happens to refrigerent in the presence of water?
HYDROLYZE, forming hydrofluoric and hydrochloric acids that will attack metals.
what will cause refrigerant to decompose?
an open flame or hot surface (1,000F)
what is caused when thermal decomposition occurs?
toxic gases such as hydrofluoric and hydrochloric acids and other extremely toxic materials are produced
what can be used to wash away particles such as dirt, scale, oil, and other contaminants that may come in contact with a refrigerating system?
HALOCARBON REFRIGERANTS AND CLEANING FLUIDS
what are refrigerants normaly stored in?
SHIPPED AND STORED LIQUEFIED, UNDER PRESSURE, IN STEEL CYLINDERS OR DRUMS.
refrigerants with lower boiling points, are shipped and stored in what kind of container?
STEEL HIGH PRESSURE CYLINDERS
refrigerants with higher boiling points such as R-11 are shipped and stored in what kind of container?
METAL DRUMS, similar to those used for oil
in sumbarines, what kind of container is all refrigerants stored in
steel cylinders to minimize leakage
what color are all military refrigerant cylinders and drums?
ORANGE, and the name of the refrigerant is stenciled on the body of the cylinder or drum. decals may also be applied to the shoulder to identify contents
cooling by an evaporating liquid was first used by who?
the ancient egyptians
why is refrigerant delivered to the evaporator or cooling coil as a liquid because it can absord heat only by what method?
vaporizing
what is required before refrigerant can be used again after leaving the cooling coil in the form of a vapor?
condensation to a liquid must occur.
who is refrigerant vapor condensed?
the laten heat surrendered by the vapor during condensation is transferred to some other medium
where is the fluid or refrigerant evaporated?
in teh cooling chamber, taking heat from the surrounding air to provide latent heat for evaporation
where does evaporating refrigerant first pass?
through tube A to the condensing chamber. it then flows through tube B back to the cooling chamber after heat has been absorbed