Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
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
|
