Revision as of 12:02, 1 June 2008 by Benstern (talk | contribs) (added links, and clarified "air" to "gas")

A compressor is basically an electrical pump that compresses gas. 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 gas tanks.

Pros/Cons of each type

12 Volt Emergency Compressor:


  • Quite cheap to buy
  • Light
  • Usually capable of 200-300 psi


  • Very slow
  • Prone to malfunction and often have a very short life.
  • Requires power source (Car battery, car battery charger, or Mains to cigarette socket transformer)
  • Noisy

Tool/Shop Compressor:


  • Reasonably cheap to run
  • Fast.
  • Won't run out, unlike gas bottles.


  • Requires power socket (if electrical).
  • Requires fuel (if gasoline powered).
  • Heavy.
  • Typically limited to 8 bar/120 psi.
  • Can be costly to buy initially.
  • Noisy

Scuba Compressor


  • Very high pressure (typically 2500-4500 psi)
  • Can be used to fill gas bottles.
  • Moderate flow


  • Very large.
  • Very expensive.
  • Noisy.
  • Power socket required.

Types of compressors

  • Reciprocating - Uses a reciprocating piston to draw gas in through a valve and force the drawn gas 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 gas 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. 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 gas causes the pressure to rise. (1)

sources: (1)