Module 2 Flashcards
a compressor with mechanically separated inlet and discharge ports
Positive-displacement compressor
a compressor with no method of separating inlet and discharge ports; permit free passage of air when not running
Dynamic compressor
a type of compressor designed for high air volume rather than high pressure
Impeller (or blower)
actual cubic feet per minute; compressor capacity measured at the intake when installed
Acfm
standard cubic feet per minute; compressor capacity specified at standard intake conditions
Scfm
Name the five kinds of positive displacement rotary compressor.
Sliding Vane Dry screw Wet screw Liquid ring Impeller
A single-stage valve compressor can normally produce discharge pressures of _____ psi.
50
Dry rotary-screw positive-displacement compressors have how many rotors?
Two
Single-stage dry rotary-screw compressors normally produce discharge pressures of _____ psi.
50
The mating lobes of a wet rotary-screw compressor are driven by the power source _____ timing gears.
Without (One lobe powers the other).
The space where the air is compressed in a liquid-ring compressor is formed by _____.
Liquid
Because of its low discharge pressure, an impeller compressor is often referred to as a _____.
Blower
To prevent contact, the impellers of an impeller compressor are _____.
Timed by external gears
The compressing impellers of a three-stage centrifugal compressor are mounted on a(n) _____.
Speed Increaser
Most centrifugal compressors are equipped with _____ and _____ to prevent excessive air temperatures.
Intercoolers; Aftercoolers
To be efficient, the rotors in dynamic compressors must rotate at _____ speeds.
High
The discharge pressure of a multistage dynamic compressor is determined by the number of stages and the _____ per _____.
Pressure per Stage
The most efficient method of controlling the output of centrifugal compressors is by _____.
Speed Variation
The rotating blades of axial-flow compressors are positioned between stationary _____ blades.
Diffuser
In plants having different compressed air requirements, it may be advantageous to install the compressor(s) in _____ location(s).
Several
The term acfm may be referred to as _____ capacity.
Free air or Actual cubic feet per minute
What is the maximum discharge pressure of a single-stage sliding-vane compressor?
50 psi
What type of positive-displacement compressor is best suited for light-duty applications?
Diaphragm
What type of compressor will deliver large amounts of oil-free air at approximately 100 psi?
Dry rotary-screw
A centrifugal compressor is classified as a(n) _____ compressor.
Dynamic
The compressing lobes of a wet rotary-screw compressor are driven without _____.
Timing gears.
The impellers of centrifugal compressors rotate at high speeds to ensure _____.
Efficient operation
Impeller compressors are frequently referred to as _____.
Blowers
The most efficient method of controlling the output of a centrifugal compressor is by _____.
Speed variation
Impeller compressors use the same operating principle as _____.
Gear pumps
The term used to describe the measured capacity of a compressor after it is installed is _____.
Actual cubic feet per minute
