FDNY A-35 with simplified answers
Air compressors power... - correct answer-(1) industrial equipment and (2) construction
tools
Examples of equipment powered by air compressor - correct answer-pneumatic
wrenches, lifts in auto service stations, paint spray booths
Air compressors enable... - correct answer-(1) efficient repair of all types of vehicles; and
(2) facilitate their safe operation on public thoroughfares
Permit is required for air compressor - correct answer-that compresses air above 100 PSI
Types of air compressors - correct answer-(1) reciprocating;
(2) centrifugal;
(3) solar; and
(4) rotary
*Difference is the way in which they compress air
How do air compressors work - correct answer-take the air in a room and force it into a
container UNDER PRESSURE. The more air forced into the container, the greater the
pressure. Compressed air can be discharged from the container at a controlled rate.
Most common air compressor - correct answer-Reciprocating
Air compressors are sometimes called - correct answer-air pumps
Air compressors can be powered by: - correct answer-(1) electric motors;
(2) internal combustion engines; or
(3) steam turbines
Explosions & air compressors - correct answer-If there is a build up of flammable gases
(ex: in service stations and workshops), those gases are heavier than air and fall to the floor
before spreading outward. These gases are easily ignited by sparks and high temperatures-
-which INCLUDES the heat generated by an air compressor.
To avoid explosions w/ air compressors - correct answer-Raise air compressor at LEAST 5
feet above ground level so that no flammable gases are drawn into the compressor. To
meet the height requirement you can place compressor on a shelf or bench OR the air
, receiver tank may be turned and stood on end w/ the air compressor bolted to the top of
the tank.
Power to air compressor - correct answer-entire unit is driven by an electric motor. Motor
activates a series of drive belts. Belts power the moving parts of the unit--like w/ power
steering and alternator in automobile
Compression Chamber operation - correct answer-Air is compressed in compression
chamber which consists of a PISTON inside a CYLINDER. Piston moves up and down.
When piston moves down -->draws air into cylinder, through INTAKE VALVE (valve
automatically opens when piston moves down).
When piston moves up-->air is compressed (intake vale automatically closes to avoid air
escaping from cylinder).
Air Reciever Operation - correct answer-When air pressure reaches a certain level, it forces
open a DISCHARGE VALVE (which is spring loaded). This releases compressed air into air
reciever (aka air tank), which is what supplies compressed air when needed.
Single Stage Air Compressor - correct answer-with one cylinder and one piston
Multi Stage Air Compressor - correct answer-with more than one piston and cylinder.
Each cylinder will increase the pressure of the air by taking air from the discharge side of
the previous cylinder and increasing the pressure to a new level. Once it reaches the last
level, the pressurized air is discharged into the reciever.
As air is compressed it becomes - correct answer-heated.
This is why in a multi stage air compressor there is an intercooler between stages of
compressor.
Exception to single stage/multi stage distinction - correct answer-CAVEAT: there are air
compressors with multiple pistons and cylinders that are single stage but these are only
the ones where each cylinder discharges directly into air receiver (unlike a true multi stage
air compressor).
Air compressors power... - correct answer-(1) industrial equipment and (2) construction
tools
Examples of equipment powered by air compressor - correct answer-pneumatic
wrenches, lifts in auto service stations, paint spray booths
Air compressors enable... - correct answer-(1) efficient repair of all types of vehicles; and
(2) facilitate their safe operation on public thoroughfares
Permit is required for air compressor - correct answer-that compresses air above 100 PSI
Types of air compressors - correct answer-(1) reciprocating;
(2) centrifugal;
(3) solar; and
(4) rotary
*Difference is the way in which they compress air
How do air compressors work - correct answer-take the air in a room and force it into a
container UNDER PRESSURE. The more air forced into the container, the greater the
pressure. Compressed air can be discharged from the container at a controlled rate.
Most common air compressor - correct answer-Reciprocating
Air compressors are sometimes called - correct answer-air pumps
Air compressors can be powered by: - correct answer-(1) electric motors;
(2) internal combustion engines; or
(3) steam turbines
Explosions & air compressors - correct answer-If there is a build up of flammable gases
(ex: in service stations and workshops), those gases are heavier than air and fall to the floor
before spreading outward. These gases are easily ignited by sparks and high temperatures-
-which INCLUDES the heat generated by an air compressor.
To avoid explosions w/ air compressors - correct answer-Raise air compressor at LEAST 5
feet above ground level so that no flammable gases are drawn into the compressor. To
meet the height requirement you can place compressor on a shelf or bench OR the air
, receiver tank may be turned and stood on end w/ the air compressor bolted to the top of
the tank.
Power to air compressor - correct answer-entire unit is driven by an electric motor. Motor
activates a series of drive belts. Belts power the moving parts of the unit--like w/ power
steering and alternator in automobile
Compression Chamber operation - correct answer-Air is compressed in compression
chamber which consists of a PISTON inside a CYLINDER. Piston moves up and down.
When piston moves down -->draws air into cylinder, through INTAKE VALVE (valve
automatically opens when piston moves down).
When piston moves up-->air is compressed (intake vale automatically closes to avoid air
escaping from cylinder).
Air Reciever Operation - correct answer-When air pressure reaches a certain level, it forces
open a DISCHARGE VALVE (which is spring loaded). This releases compressed air into air
reciever (aka air tank), which is what supplies compressed air when needed.
Single Stage Air Compressor - correct answer-with one cylinder and one piston
Multi Stage Air Compressor - correct answer-with more than one piston and cylinder.
Each cylinder will increase the pressure of the air by taking air from the discharge side of
the previous cylinder and increasing the pressure to a new level. Once it reaches the last
level, the pressurized air is discharged into the reciever.
As air is compressed it becomes - correct answer-heated.
This is why in a multi stage air compressor there is an intercooler between stages of
compressor.
Exception to single stage/multi stage distinction - correct answer-CAVEAT: there are air
compressors with multiple pistons and cylinders that are single stage but these are only
the ones where each cylinder discharges directly into air receiver (unlike a true multi stage
air compressor).
