Compressor
A compressor is basically an electrical pump that compresses air. They range from small 12 Volt emergency compressors with relatively high pressure but very low volume, to shop compressors with big air tanks for storage, and scuba compressors that can deliver thousands of psi to fill portable air tanks.
Pros/Cons of each type
12 Volt Emergency Compressor:
Advantages:
- Quite cheap to buy
- Light
- Usually capable of 200-300 psi
Disadvantages:
- Very slow
- Prone to malfunction and short life.
- Requires power source (either Car battery, or Mains to cigarette socket transformer)
- Noisy
Tool/Shop Compressor:
Advantages:
- Reasonably cheap to run
- Won't run out, unlike gas bottles.
Disadvantages:
- Requires power socket (if electrical).
- Requires fuel (if gas powered).
- Heavy.
- Typically limited to 8 bar/120 psi.
- Can be costly to buy initially.
- Noisy
Scuba Compressor
Advantages:
- Very high pressure (typically 2500-4500 psi)
- Can be used to fill gas bottles.
- Moderate flow
Disadvantages:
- Very large.
- Very expensive.
- Noisy.
- Power socket required.
Types of compressors
- Reciprocating - Uses a reciprocating piston to draw air in through a valve and force the drawn air into a storage tank or through a smaller orifice. They are available with single or multiple cylinders, depending upon the pressure and volume required. Reciprocating compressors are referred to as positive displacement compressors. (1)
- Rotary Screw - Two intermeshing helical rotors in a twin bore case are used to compress between one convex and one concave rotor. The trapped volume of air is decreased while the pressure is increased. Rotary screw compressors are referred to as positive displacement compressors. (1)
- Centrifugal Compressor - Unlike the reciprocating and rotary screw compressors, centrifugal compressors do not make use of positive displacement. Air or gas enters the center of rotation of an element and is forced outward. The element can use curved blades, radial blades, or backward blades. The acceleration of the air causes the pressure to rise. (1)
sources: (1) http://www.ctrlsys.com/library/applications/compressors-2.php
