_______ on centrifugal air compressors are provided in order to control the amount of air flowing to the impeller and thus control the capacity of the unit.
Adjustable inlet vanes
Adjustable diffuser vanes
Variable frequency drive
Moving and fixed blades
Dummy piston
The aftercooler is used in an air compression system to cool the:
Air after the first stage of compression
Lubricating oil of large axial compressors
Air after it leaves the receiver
Air after the last stage of compression
Air before being compressed
Positive displacement compressor types include: 1. Sliding vane 2. Axial flow 3. Internal gear 4. Volute casing 5. Rotary screw 6. Multi lobe
1,3,4,6
2,4,5,6
1,3,5,6
1,2,4,5
2,3,5,6
Effective intercooling will reduce weakening of parts due to high temperatures, and reduce possibility of:
Compressor explosions
Water hammer
Compressor implosions
Compressor leaks
Corrosion
In the variable speed control method the compressor output is regulated by:
Adjustment of clearance pockets
Valve unloaders
A safety relief valve
A driver that can be throttled
A method of unloading a reciprocating compressor is to:
Hold the discharge valve closed
Hold the discharge valve open
Place a check valve in the discharge line
Hold the inlet valves in the open position
Unloading a cylinder
The flow of air from a compressor must be _______ to suit the load requirements and to maintain constant pressure in the system.
Increased
Decreased
Dampened
Interrupted
Regulated
To prevent surging, the load on the compressor must not be allowed to fall below the:
Surge limit
Maximum volume
Related point
Rated pressure
Set point
The ________ control method can be used when a compressor is driven by a steam engine, a turbine, or an internal combustion engine.
Constant speed
Start and stop
Dual
Start and stop in conjunction with constant speed
Variable speed
